1) Put 5 boats.wmv in the timeline
2) Produce to H.265 HEVC, MP4, 1920x1080/30p (11 Mbps) will be fine
3) Remove the 5 boats.wmv from the timeline and add the produced file from item 2 to timeline
4) In "Preferences" > "Hardware Acceleration" make sure "Enable hardware decoding" is checked
5) Produce to H.264 AVC, M2TS, 1920x1080/60i (16Mbps)

Item 5 appears to work partially but the full video is not produced, only a small fraction of the timeline.

6) Move the timeline content slightly downstream so a blank spot occurs at the beginning of the timeline
7) Produce to H.264 AVC, M2TS, 1920x1080/60i (16Mbps)

Item 7 works fine

8) Move the timeline content back to 0:00
9) Add a Fx to the first few seconds
10) Produce to H.264 AVC, M2TS, 1920x1080/60i (16Mbps)

Item 10 works fine

Above issue occurs with several different Nvidia GPU's, WIN7, WIN10, and several created H.265 source profiles and containers created from the boats.wmv (Item 2) and also with several desired output profiles/containers like H.264, MPEG-2...so on (Item 5)

Basically keeping "Enable hardware decoding" unchecked in "Preferences" will circumvent the issue, it's still a implementation limitation, CL, have a look.

Jeff