Not a bug in NetworkManager; something's happening at the driver level or between wpasupplicant and the driver:

Jan  2 10:40:53 ubuntu-phablet kernel: [  595.283020] wl_bss_connect_done succeeded with 74:ea:3a:af:cc:bc
Jan  2 10:40:53 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: completed -> 4-way handshake
Jan  2 10:40:53 ubuntu-phablet wpa_supplicant[1320]: wlan0: WPA: Key negotiation completed with 74:ea:3a:af:cc:bc [PTK=CCMP GTK=TKIP]
Jan  2 10:40:53 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: 4-way handshake -> completed
Jan  2 10:40:53 ubuntu-phablet wpa_supplicant[1320]: wlan0: Associated with 74:ea:3a:af:cc:bc
Jan  2 10:40:53 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: completed -> associated
Jan  2 10:41:03 ubuntu-phablet wpa_supplicant[1320]: wlan0: Authentication with 74:ea:3a:af:cc:bc timed out.
Jan  2 10:41:03 ubuntu-phablet kernel: [  605.372955] CFG80211-ERROR) wl_cfg80211_disconnect : Reason 3
Jan  2 10:41:03 ubuntu-phablet kernel: [  605.398223] cfg80211: Calling CRDA to update world regulatory domain
Jan  2 10:41:03 ubuntu-phablet wpa_supplicant[1320]: wlan0: CTRL-EVENT-DISCONNECTED bssid=00:00:00:00:00:00 reason=0
Jan  2 10:41:03 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: associated -> disconnected
Jan  2 10:41:04 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: disconnected -> scanning
Jan  2 10:41:04 ubuntu-phablet kernel: [  606.529968] max17040 4-0036: online = 1 vcell = 3953750 soc = 91 status = 2 health = 1 temp = 380 charger status = 0
Jan  2 10:41:05 ubuntu-phablet wpa_supplicant[1320]: wlan0: Trying to associate with 74:ea:3a:af:cc:bc (SSID='davmor2' freq=2462 MHz)
Jan  2 10:41:05 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: scanning -> associating
Jan  2 10:41:05 ubuntu-phablet kernel: [  607.475616] wl_bss_connect_done succeeded with 74:ea:3a:af:cc:bc
Jan  2 10:41:05 ubuntu-phablet wpa_supplicant[1320]: wlan0: Associated with 74:ea:3a:af:cc:bc
Jan  2 10:41:05 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: associating -> 4-way handshake
Jan  2 10:41:05 ubuntu-phablet wpa_supplicant[1320]: wlan0: WPA: Key negotiation completed with 74:ea:3a:af:cc:bc [PTK=CCMP GTK=TKIP]
Jan  2 10:41:05 ubuntu-phablet wpa_supplicant[1320]: wlan0: CTRL-EVENT-CONNECTED - Connection to 74:ea:3a:af:cc:bc completed (reauth) [id=0 id_str=]
Jan  2 10:41:05 ubuntu-phablet NetworkManager[927]: <info> (wlan0): supplicant interface state: 4-way handshake -> completed
Jan  2 10:41:05 ubuntu-phablet kernel: [  607.546051] wl_bss_connect_done succeeded with 74:ea:3a:af:cc:bc

This may be related to the warning that sometimes appears in syslog:

Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285156] Resume caused by IRQ 162, bcmsdh_sdmmc
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285156]    PD_AUDIO curr=ON prev=ON logic=ON
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285156]          AUDIO ENGINE mode=ENABLED stbyst=ON idlest=ON
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285156]          MCPDM mode=ENABLED idlest=ON
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285156]          CM1_ABE enabled=0x100
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285156] Powerdomain (abe_pwrdm) didn't enter target state 0 Vs achieved state 3. current state 3
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285156] Could not enter target state in pm_suspend
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285247] Suspended for 9.163 seconds
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.285430] Enabling non-boot CPUs ...
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.301910] CPU1: Booted secondary processor
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.303955] Switched to NOHz mode on CPU #1
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.304046] CPU1 is up
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.305786] PM: early resume of devices complete after 1.708 msecs
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.401306] wakeup wake lock: wlan_wake
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.402893] wl_bss_connect_done succeeded with 74:ea:3a:af:cc:bc
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.423797] PM: resume of devices complete after 117.706 msecs
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.423828] ------------[ cut here ]------------
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.423889] WARNING: at /build/buildd/linux-maguro-3.0.0/net/wireless/sme.c:578 __cfg80211_roamed+0x21c/0x23c()
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.423889] Modules linked in:
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.423919] Backtrace: 
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.423980] [<c0056748>] (dump_backtrace+0x0/0x10c) from [<c0643228>] (dump_stack+0x18/0x1c)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424011]  r6:c0850b0c r5:00000242 r4:00000000 r3:271aed03
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424072] [<c0643210>] (dump_stack+0x0/0x1c) from [<c00a3128>] (warn_slowpath_common+0x54/0x6c)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424133] [<c00a30d4>] (warn_slowpath_common+0x0/0x6c) from [<c00a3164>] (warn_slowpath_null+0x24/0x2c)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424163]  r8:c6435e28 r7:00000000 r6:c6435e10 r5:c088cf28 r4:c7328600
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424194] r3:00000009
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424224] [<c00a3140>] (warn_slowpath_null+0x0/0x2c) from [<c062a6b0>] (__cfg80211_roamed+0x21c/0x23c)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424285] [<c062a494>] (__cfg80211_roamed+0x0/0x23c) from [<c0613160>] (cfg80211_process_wdev_events+0x120/0x19c)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424346] [<c0613040>] (cfg80211_process_wdev_events+0x0/0x19c) from [<c0614118>] (cfg80211_process_rdev_events+0x40/0x7c)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424407] [<c06140d8>] (cfg80211_process_rdev_events+0x0/0x7c) from [<c0611ae0>] (cfg80211_event_work+0x2c/0x5c)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424438]  r6:c0905620 r5:c736000c r4:c7360000 r3:c0611ab4
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424499] [<c0611ab4>] (cfg80211_event_work+0x0/0x5c) from [<c00bee40>] (process_one_work+0x134/0x4b0)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424530]  r5:c7bde000 r4:c7bc4f00
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424560] [<c00bed0c>] (process_one_work+0x0/0x4b0) from [<c00bf518>] (worker_thread+0x144/0x314)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424591] [<c00bf3d4>] (worker_thread+0x0/0x314) from [<c00c4180>] (kthread+0x8c/0x94)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424652] [<c00c40f4>] (kthread+0x0/0x94) from [<c00a72c4>] (do_exit+0x0/0x354)
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424682]  r6:c00a72c4 r5:c00c40f4
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424682] PM: Finishing wakeup.
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424713] Restarting tasks ...  r4:c7845ea0
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424743] Board Information: Tuna HW revision: 09 (Maguro 8th Sample), cpu OMAP4460 ES1.1 
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.424774] ---[ end trace c22f262dd1e7fad2 ]---
Jan  2 10:42:50 ubuntu-phablet kernel: [  644.464721] done.

Reassigning to linux.