Flow Stuck in Running & Can't be Saved

I have a flow that was perfectly running before and has suddenly stopped working since a few weeks ago. It just kept getting stuck in the “running” state and never finished. When I go to edit the flow, I see the error below:
In logs I see this. Do note that I have a couple of flows like this one that are just forever stuck in running, and they were all created before the last two updates. Flows created after the last two updates work just fine.

Hello @Debate,

Could you please share details of the workflow, including instructions on how to reproduce it?

Thank you.