Found bug in my test

Hi,
This is a great app we have been looking for as the base template we can expand for our project. But when I installed it as instructed, I found following issue:

After I send a question in the chat, I got no response at all. but if I send another question, I started to get the response for the first question. Tried for new fresh installation, got the same problem.

The only change I made is the region: I replaced the region from ap-southeast-1 to us-east-1 in the template.ts.

Please let me know if I am the only one experiencing this and any idea what is wrong?

Thanks,
Brian Liu