[Bug]: Studio enters never ending error loop if multiple chats in same session

[SailorJoe6]

Describe the bug

Latest version of Studio sometimes goes into a never ending error loop when there are multiple chats in the same session. This is related to the switch from Synchronous to Asynchronous execution which was part of enabling Human Input in Studio. The problem only occurs in some session, but once it occurs there that session is pretty much dead.

The issue is my fault. I have a fix, I'll post a PR in a moment.

Steps to reproduce

See the video. Seems to occur intermittently, but it's easiest to reproduce in a Session with a Group Chats after finishing the chat, then starting another chat, etc.

Model Used

gpt-4o

Expected Behavior

Should have an error loop

Screenshots and logs

Here's a video of the problem from the users point of view: https://www.loom.com/share/d2537fda2d5947479d8abe37e81976b6?sid=0555aa9f-8963-4fbd-8607-df9fe683b607

And here's a video of the problem with breakpoints in the code and a technical explanation.
https://www.loom.com/share/25a5c8027bdb4f80aae63c77180bd2fb?sid=a27761e5-cbb9-4090-9ae6-9e5565fbd590

Additional Information

No response