So now I've got a dump of /proc/modules from 16.04.4 (4.13) and the issue is much more apparent:
ubuntu@xwing:~$ cat /proc/modules 
nls_iso8859_1 16384 1 - Live 0x0000000000000000
ppdev 20480 0 - Live 0x0000000000000000
intel_rapl 20480 0 - Live 0x0000000000000000
x86_pkg_temp_thermal 16384 0 - Live 0x0000000000000000
intel_powerclamp 16384 0 - Live 0x0000000000000000
coretemp 16384 0 - Live 0x0000000000000000
kvm_intel 204800 0 - Live 0x0000000000000000
joydev 20480 0 - Live 0x0000000000000000
input_leds 16384 0 - Live 0x0000000000000000
kvm 589824 1 kvm_intel, Live 0x0000000000000000
irqbypass 16384 1 kvm, Live 0x0000000000000000
intel_cstate 20480 0 - Live 0x0000000000000000
intel_rapl_perf 16384 0 - Live 0x0000000000000000
mei_me 40960 0 - Live 0x0000000000000000
lpc_ich 24576 0 - Live 0x0000000000000000
wmi_bmof 16384 0 - Live 0x0000000000000000
mei 102400 1 mei_me, Live 0x0000000000000000
ie31200_edac 16384 0 - Live 0x0000000000000000
shpchp 36864 0 - Live 0x0000000000000000
parport_pc 32768 0 - Live 0x0000000000000000
parport 49152 2 ppdev,parport_pc, Live 0x0000000000000000
mac_hid 16384 0 - Live 0x0000000000000000
ib_iser 49152 0 - Live 0x0000000000000000
rdma_cm 57344 1 ib_iser, Live 0x0000000000000000
iw_cm 45056 1 rdma_cm, Live 0x0000000000000000
ib_cm 49152 1 rdma_cm, Live 0x0000000000000000
ib_core 217088 4 ib_iser,rdma_cm,iw_cm,ib_cm, Live 0x0000000000000000
iscsi_tcp 20480 0 - Live 0x0000000000000000
libiscsi_tcp 20480 1 iscsi_tcp, Live 0x0000000000000000
libiscsi 53248 3 ib_iser,iscsi_tcp,libiscsi_tcp, Live 0x0000000000000000
scsi_transport_iscsi 98304 4 ib_iser,iscsi_tcp,libiscsi, Live 0x0000000000000000
autofs4 40960 2 - Live 0x0000000000000000
btrfs 1101824 0 - Live 0x0000000000000000
raid10 49152 0 - Live 0x0000000000000000
raid456 143360 0 - Live 0x0000000000000000
async_raid6_recov 20480 1 raid456, Live 0x0000000000000000
async_memcpy 16384 2 raid456,async_raid6_recov, Live 0x0000000000000000
async_pq 16384 2 raid456,async_raid6_recov, Live 0x0000000000000000
async_xor 16384 3 raid456,async_raid6_recov,async_pq, Live 0x0000000000000000
async_tx 16384 5 raid456,async_raid6_recov,async_memcpy,async_pq,async_xor, Live 0x0000000000000000
xor 24576 2 btrfs,async_xor, Live 0x0000000000000000
hid_generic 16384 0 - Live 0x0000000000000000
hid_logitech_hidpp 32768 0 - Live 0x0000000000000000
hid_logitech_dj 20480 0 - Live 0x0000000000000000
usbhid 49152 0 - Live 0x0000000000000000
hid 118784 4 hid_generic,hid_logitech_hidpp,hid_logitech_dj,usbhid, Live 0x0000000000000000
raid6_pq 118784 4 btrfs,raid456,async_raid6_recov,async_pq, Live 0x0000000000000000
libcrc32c 16384 1 raid456, Live 0x0000000000000000
raid1 40960 0 - Live 0x0000000000000000
raid0 20480 0 - Live 0x0000000000000000
multipath 16384 0 - Live 0x0000000000000000
linear 16384 0 - Live 0x0000000000000000
i915 1830912 1 - Live 0x0000000000000000
crct10dif_pclmul 16384 0 - Live 0x0000000000000000
crc32_pclmul 16384 0 - Live 0x0000000000000000
ghash_clmulni_intel 16384 0 - Live 0x0000000000000000
pcbc 16384 0 - Live 0x0000000000000000
aesni_intel 188416 0 - Live 0x0000000000000000
drm_kms_helper 167936 1 i915, Live 0x0000000000000000
aes_x86_64 20480 1 aesni_intel, Live 0x0000000000000000
syscopyarea 16384 1 drm_kms_helper, Live 0x0000000000000000
crypto_simd 16384 1 aesni_intel, Live 0x0000000000000000
igb 217088 0 - Live 0x0000000000000000
glue_helper 16384 1 aesni_intel, Live 0x0000000000000000
cryptd 24576 3 ghash_clmulni_intel,aesni_intel,crypto_simd, Live 0x0000000000000000
sysfillrect 16384 1 drm_kms_helper, Live 0x0000000000000000
e1000e 249856 0 - Live 0x0000000000000000
dca 16384 1 igb, Live 0x0000000000000000
sysimgblt 16384 1 drm_kms_helper, Live 0x0000000000000000
ahci 36864 0 - Live 0x0000000000000000
i2c_algo_bit 16384 2 i915,igb, Live 0x0000000000000000
fb_sys_fops 16384 1 drm_kms_helper, Live 0x0000000000000000
libahci 32768 1 ahci, Live 0x0000000000000000
drm 360448 3 i915,drm_kms_helper, Live 0x0000000000000000
ptp 20480 2 igb,e1000e, Live 0x0000000000000000
megaraid_sas 139264 2 - Live 0x0000000000000000
pps_core 20480 1 ptp, Live 0x0000000000000000
wmi 24576 1 wmi_bmof, Live 0x0000000000000000
video 40960 1 i915, Live 0x0000000000000000