I have the exact same on a Mid 2015 macbook pro on Mojave 10.14.2
Stackshot Reason: Sleep transition timed out after 180 seconds while entering darkwake on way to sleep. Suspected bundle: com.apple.iokit.IOGraphicsFamily. Thread 0x74.
Failure code:: 0xc5617ac3 00000031
...
Process: kernel_task [0]
UUID: 56B30885-F9BA-30E8-AD1C-5D59EC243BA9
Architecture: x86_64
Version: Darwin Kernel Version 18.2.0: Mon Nov 12 20:24:46 PST 2018; root:xnu-4903.231.4~2/RELEASE_X86_64
Footprint: 132.06 MB
Start time: 2019-01-16 05:53:54 +0100
End time: 2019-01-16 05:53:54 +0100
Num samples: 1 (1)
...
Binary Images:
*0xffffff7f81122000 - ??? ??? <C5617AC3-A68D-36CE-AC22-7C7C81318961>
*0xffffff7f8156e000 - ??? ??? <FA92A03C-F113-384A-9B1F-B2C52DE7F4D2>
*0xffffff7f81bbb000 - ??? ??? <60380132-AE9F-3720-B7BF-1653155D78BD>
*0xffffff7f81e48000 - ??? ??? <FB5F5585-D0DB-3B4C-A4ED-7E39C196693B>
*0xffffff7f83377000 - 0xffffff7f83408fff IOBluetoothFamily (6009.4.2) <6437483C-5DDE-3E8F-92B5-2F890F3BC952> /System/Library/Extensions/IOBluetoothFamily.kext/Contents/MacOS/IOBluetoothFamily
*0xffffff7f83d60000 - ??? ??? <F677275E-0C32-3CCB-9AE8-FD02558657AB>
*0xffffff7f87075000 - ??? ??? <E8502198-6395-35AA-9DBD-35AD93251D37>
*0xffffff8000200000 - ??? ??? <56B30885-F9BA-30E8-AD1C-5D59EC243BA9>
What is apple doing about this!?