Horizon stuck on BadSequenceNumber error.

[l3utterfly]

What version are you using?

Horizon 2.15.1 Go v1.17

What did you do?

Submitted a transaction with a bad sequence number.

Horizon is running on non-ingest mode, directly connected a stellar core.

What did you expect to see?

Horizon immediately returning error to client.

What did you see instead?

Horizon seems to have obtained the error from the core. Then gets stuck. Only after the client closed the connection, did Horizon respond with http status 499.

Note the timestamps in the above screenshots from Horizon log. The error was already obtained around 11:42. However, it took Horizon over 2 minutes to respond to the client http request.