I have a series of separate projects that all contain a number of still images (number varying between 15 and 80) that need to be displayed in some order. After the 3rd or 4th project with those images the thumbnails of those image are going astray. I see no thumbnails, or thumbnails that belong to titles, or effects etc. PD is still very consequent with those, once it has appointed a (wrong) thumbnail to an image, it will display that thumbnail in the media room and in the timeline. Only when I run a preview, the images are shown.
Cleaning the cache will not (immediately) help. Restarting PD always helps. But it still very anying and also, it happens to me already many PD versions and in the many computer systems I have had in that period. I have shared the ordeal with you in this forum, and with CL. I have reported it to CL again for this version (21), and they come back asking me all sorts of (standard) questions and files and screen shots, which I will try to collect. Although they should be able to reproduce this themselves.
This has something to do with memory management, or the like, which of course will grow with the large number of effects and other goodies in PD.
I am sharing this again, also wondering whether you have seen this behaviour too, or is it just me an my regular projects with many still images?