Preview Files disappear when clicking 'Edit Original ' on linked After Effects comps

[mickwalkerboxset]

This has happened so much over the years.

And I am at a loss as to why.

I'll have a sequence in Premiere Pro full of all sorts including linked After Effects comps.

I'll Render It all, it's all 'green' with preview files. I save the project , close it, open it up again a few days later - previews are all stil there.

BUT

When I then go to tweak a linked After Effects comp by going to 'Edit Original' on the timeline - all the previews disappear and my timeline is now back to unrendered 'red' and not rendered 'green'.

Can anyone help me as I'm at a loss as to why this happens! It's happened for years on several projects, on serveral devices! Is it me? Am I cursed....?

[Bruce Bullis]

If you've changed anything about that linked AE comp, blowing cache is the right answer. 

Are you saving changes to the .aep containing the linked comp?