Also happening on:
Linux pebble 4.2.0-18-generic #22-Ubuntu SMP Fri Nov 6 18:25:50 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

$ dmidecode -s bios-version
RYBDWi35.86A.0348.2015.0703.1124

Release notes for 0350 BIOS don't mention anything regarding graphics changes, just a fix for some audio bug.

$ lspci -s 00:02.0 -v
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U Integrated Graphics (rev 09) (prog-if 00 [VGA controller])
        Subsystem: Intel Corporation Device 2057
        Flags: bus master, fast devsel, latency 0, IRQ 45
        Memory at a9000000 (64-bit, non-prefetchable) [size=16M]
        Memory at b0000000 (64-bit, prefetchable) [size=256M]
        I/O ports at 3000 [size=64]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
        Capabilities: [d0] Power Management version 2
        Capabilities: [a4] PCI Advanced Features
        Kernel driver in use: i915

[10685.158305] WARNING: CPU: 2 PID: 797 at /build/linux-jJX2Dm/linux-4.2.0/drivers/gpu/drm/i915/intel_display.c:1365 assert_plane.constprop.98+0x6f/0x90 [i915]()
[10685.158306] plane A assertion failure (expected on, current off)
[10685.158340] Modules linked in: drbg ansi_cprng ctr ccm rfcomm bnep input_leds nls_iso8859_1 btusb btrtl btbcm btintel hid_generic bluetooth usbhid arc4 snd_soc_rt5640 snd_soc_rl6231 intel_rapl snd_soc_core iosf_mbi x86_pkg_temp_thermal intel_powerclamp snd_compress coretemp ac97_bus snd_pcm_dmaengine kvm_intel snd_seq_midi kvm snd_seq_midi_event iwlmvm crct10dif_pclmul crc32_pclmul mac80211 snd_rawmidi ghash_clmulni_intel aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd snd_seq iwlwifi snd_hda_codec_realtek snd_hda_codec_hdmi snd_seq_device snd_hda_codec_generic snd_hda_intel serio_raw snd_hda_codec cfg80211 snd_hda_core snd_hwdep snd_pcm mei_me shpchp snd_timer lpc_ich ir_lirc_codec ir_xmp_decoder lirc_dev ir_mce_kbd_decoder ir_sharp_decoder ir_sanyo_decoder ir_sony_decoder mei
[10685.158360]  ir_jvc_decoder ir_rc6_decoder ir_rc5_decoder ir_nec_decoder snd soundcore rc_rc6_mce snd_soc_sst_acpi nuvoton_cir dw_dmac rc_core dw_dmac_core 8250_dw acpi_pad i2c_designware_platform i2c_designware_core acpi_als spi_pxa2xx_platform mac_hid kfifo_buf industrialio parport_pc ppdev lp parport autofs4 i915 e1000e i2c_algo_bit psmouse ptp drm_kms_helper ahci drm libahci pps_core video i2c_hid hid sdhci_acpi sdhci
[10685.158363] CPU: 2 PID: 797 Comm: Xorg Not tainted 4.2.0-18-generic #22-Ubuntu
[10685.158363] Hardware name:                  /NUC5i5RYB, BIOS RYBDWi35.86A.0348.2015.0703.1124 07/03/2015
[10685.158367]  0000000000000000 000000004010fe72 ffff88024b2fb718 ffffffff817e8c09
[10685.158369]  0000000000000000 ffff88024b2fb770 ffff88024b2fb758 ffffffff8107b3c6
[10685.158370]  0000000000000000 0000000000000000 ffff880248340000 ffff88024cf63000
[10685.158371] Call Trace:
[10685.158376]  [<ffffffff817e8c09>] dump_stack+0x45/0x57
[10685.158379]  [<ffffffff8107b3c6>] warn_slowpath_common+0x86/0xc0
[10685.158381]  [<ffffffff8107b455>] warn_slowpath_fmt+0x55/0x70
[10685.158398]  [<ffffffffc021514f>] assert_plane.constprop.98+0x6f/0x90 [i915]
[10685.158414]  [<ffffffffc021ed59>] hsw_disable_ips+0x39/0x180 [i915]
[10685.158428]  [<ffffffffc021eef4>] intel_pre_disable_primary+0x54/0x90 [i915]
[10685.158442]  [<ffffffffc021ef6a>] intel_crtc_disable_planes+0x3a/0x100 [i915]
[10685.158456]  [<ffffffffc021f8c6>] __intel_set_mode+0x226/0xb60 [i915]
[10685.158471]  [<ffffffffc0226d16>] intel_crtc_set_config+0x2b6/0x580 [i915]
[10685.158485]  [<ffffffffc00964c6>] drm_mode_set_config_internal+0x66/0x100 [drm]
[10685.158491]  [<ffffffffc010c632>] restore_fbdev_mode+0xc2/0xf0 [drm_kms_helper]
[10685.158497]  [<ffffffffc010e4e9>] drm_fb_helper_restore_fbdev_mode_unlocked+0x29/0x70 [drm_kms_helper]
[10685.158501]  [<ffffffffc010e552>] drm_fb_helper_set_par+0x22/0x40 [drm_kms_helper]
[10685.158517]  [<ffffffffc02343ba>] intel_fbdev_set_par+0x1a/0x60 [i915]
[10685.158521]  [<ffffffff81287d02>] ? ext4_mark_iloc_dirty+0x462/0x710
[10685.158524]  [<ffffffff81447f16>] fb_set_var+0x236/0x460
[10685.158527]  [<ffffffff812d40cf>] ? jbd2_journal_dirty_metadata+0xbf/0x240
[10685.158530]  [<ffffffff812b7d08>] ? __ext4_handle_dirty_metadata+0x48/0x1f0
[10685.158533]  [<ffffffff812332c3>] ? __find_get_block+0xd3/0x100
[10685.158536]  [<ffffffff8143e1a2>] fbcon_blank+0x312/0x360
[10685.158538]  [<ffffffff812d40cf>] ? jbd2_journal_dirty_metadata+0xbf/0x240
[10685.158541]  [<ffffffff814d39f3>] do_unblank_screen+0xd3/0x1a0
[10685.158543]  [<ffffffff814c8eda>] vt_ioctl+0x50a/0x12f0
[10685.158545]  [<ffffffff811dd916>] ? __slab_free+0xb6/0x2c0
[10685.158548]  [<ffffffff814bc19c>] tty_ioctl+0x3cc/0xbb0
[10685.158551]  [<ffffffff811a7481>] ? kzfree+0x31/0x40
[10685.158552]  [<ffffffff811dde96>] ? kfree+0x126/0x130
[10685.158555]  [<ffffffff812108a5>] do_vfs_ioctl+0x295/0x480
[10685.158557]  [<ffffffff8121d7a4>] ? mntput+0x24/0x40
[10685.158559]  [<ffffffff811fef30>] ? __fput+0x190/0x220
[10685.158562]  [<ffffffff81210b09>] SyS_ioctl+0x79/0x90
[10685.158564]  [<ffffffff817ef9f2>] entry_SYSCALL_64_fastpath+0x16/0x75
[10685.158566] ---[ end trace 628f0dd29de1b3e9 ]---

These messages also frequently appear in dmesg:
[10685.248773] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!
[10685.249135] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!
[10685.259859] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!
[10685.260221] [drm:gen8_irq_handler [i915]] *ERROR* The master control interrupt lied (SDE)!

This is dubious, but the reason I was paying attention is Xorg (at least the display) getting into a weird locked up state (screen not updating until I restart X) when switching video modes (I think), specifically when Steam (the game thingy) in "big picture mode" tries to run a game. But this could also very well just be Steam doing something wrong (it's a new system so I'm not sure where the fault might lie).