hi, Vic.
yes sounds like this could be the problem.
what you need to do is to set you sequence preset to match your clip’s settings.
this is simple enough, but not automatic.
you need to go to your FCP menu > AV Settings,
hunt through the available sequence settings in there till you find the right one,
and select that.
NOTE: you need to click in the column on the left and get a check mark or tick on it, not just a highlight, otherwise it is not selected.
another approach to this is to use the Easy Set-Up window.
yet another approach is to just create a new sequence, edit a clip in, say YES you want it to match,
delete the clip , then drag your sequence in.
but that is boring to do every time. (only ok if you are in panic mode!)
next, make sure it has worked:
make a new sequence, edit a clip into it.do you get the warning?
no, then good
now make a new sequence and drag your edit sequence into it as a nest.
should work, fingers crossed.
finally, i would say that ProResLT might not be best for you.
it is a slightly lower quality (hard to see, i know) and definitely not great for compositing.
i use LT for off-line editing, where i cut at a lower res to save disk space.
i found that when i re-built my effects using the camera original (ProRes4444) they rendered faster than the LT did.
something to do with the greater compression, (and the “Dithering” process in LT, i was advised)
i would suggest you use ProRes422
cheers,
nick