Project froze, "Workspace Update Error: Serialized variable type with id ... had type list, and does not match variable field that references it"

[fsih]

Expected Behavior

Project doesn't freeze

Actual Behavior

Project froze with this error in the console
https://pastebin.com/TYLnRadA

Steps to Reproduce

I don't remember what happened
):

Operating System and Browser

Windows Firefox

[thisandagain]

Unfortunately not enough info to perform a repro. Closing for now.