I have an existing automation rule that has been running without issues until last week, when I encountered the following error which I've never seen before:

This automation rule fails when it's cloning the issue into another project. After I removed the epic link and ran the automation again, the issue cloned successfully.
Other notes:
- The epic is not used in the automation rule. The automation rule only copies the description and summary.
- This rule was working previously both for tickets linked to epics and tickets without epics.
Does anyone know what could be causing this issue?