Fresh install of 15b7 won't show color graded clips

I've just installed DR15 Beta 7 and opened a project I was working on in 15 Beta 6.

When the project opened in the Edit tab the clip that the cursor was on loaded as normal and played through in the viewer but every other clip shows up and plays as black. This also happens in the Color tab.

The only way to view the clips in either tab is by bypassing the color grade, which isn't very helpful.

Does anybody know how to fix this?

[Peter Chamberlain]

What do you see on a new project?
On the bad project do you have any Fusion effects?

A new project is just like normal, and other projects are functioning as normal too.

With the problematic project none of the clips have any nodes in the Fusion tab, not even Media In/Out nodes. I had to delete these because they were causing the clips to drop frames at their I/O points in the Editing timeline. I posted about this issue here: viewtopic.php?f=21&t=76836

If I add Media I/O nodes in the Fusion tab the clips appear in the Editing viewer like normal, but they're still dropping frames at their I/O points on the timeline...