Replace with After Effects Composition crashes BOTH Premiere and After Effects

[cmodonn]

Mac OSX 10.15.7

Premiere - 15.1.0

After Effects - 18.1.0

This problem has just occurred on a project I've been working on for days. I've round-tripped/Dynamic Linked clips on this very project with no problem, but now it's a total application crash.

I am working with RED footage (with ProRes Proxies), but the RED footage and proxies transferred between the apps just fine a mere 24 hours ago. Same project files (.pproj and .aep). Even if I create new projects and load the footage in Pr, the same error happens. Opened up previous projects using HD footage and it causes a crash as well.

I did notice today that AE was giving me scripting errors for two of the UIScripts I use (Motion 2 and EaseCopy from aescripts). Uninstalled and reinstalled both scripts... same issue.

Uninstalled and reinstalled both Pr and AE... same issue. Uninstalled and reinstalled entire Creative Cloud apps and main Creative Cloud app, same issue. 

Other than jumping back to 2020, any ideas on a solution?