XNote window stopped working in TB 90

[zevrix]

First, I know TB 90 is still in beta. BUT, unlike the released TB 78, it doesn't crash constantly.

XNote actually did work normally for at least a week in TB 90. It just stopped now for unclear reason. Maybe after updating to 90b3? Not sure.

Now I get the attached error in the XNote window, which makes any editing and creating new notes impossible.

Other aspects are not affected - that is, existing notes are shown in the column and the body of the message.

macOS 11.4