one possible way to avoid speed-change weirdness when Media Managing:
find all your speed modifued clips in your timeline (involves a boring manual search)
place copies of them at the end of your program.
remove attibutes: Speed, so you have just the unafected frames you need.
this has been known to “protect” the speed mod shots from weirdness.
and if it doesnt, then at least you have the frames you need to re-build the effects.
rather than putting the shots at the end of the timeline,
another approach would be to create a new track JUST for these shots.
then you could have the un-modified versions sitting direclty above the modified ones.
nick