When i reopen a clip with MBL applied, the poster frame i get is from the previous clip.
You are talking about the image within the MBL UI, correct?
Are you going through the timeline from clip to clip
opening the MBL interface for each clip as you go along?
If so, it wouldn't surprise me if the MBL frame buffer
is having trouble keeping up with you.
Maybe try opening the MBL UI and if you get a frame from
the previous clip, exit, scrub to a new spot in the clip and re-try.
I was thinking of clearing the cache...
I doubt the Pr cache has any effect on the MBL UI.