recently i did a simple sequence with some overblending of credits. i just used the slider on top of the clip to define the ramp for fade in:
later i had to produce a slow motion variant of the sequence. i generated a compound clip of the whole sequence, put it on a new timeline, and did a 50% optical flow retime of the compound clip. but at the beginning of the smooth fade ins i always got a flash of one single frame, where the overlay is 100% visible!
you could take a look at 1:03:07:02 in "timeline2" of this
project file.
i used resolve 12.5 on [virtualized] win8.1.