What happened?
If I go into "Archived Calls" and then "Add Archived Call" and create a call in this way, the call ID ends up being the same as the previous call. I suspect there's a slight bug here with the Call ID counter not being incremented correctly!
I have uploaded a screenshot of the result, with sensitive information omitted.

If I then go into "active calls" and create a new call in the normal way, the counter increments as expected. For the record, I also did not use the "Regenerate Call Numbers" option.
Issue was observed on ResGrid version 3.5.0.0 while using MS Edge 130 (arm64) on MacOS 15.1.