My Webhook doesn't trigger aws codepipeline ( on certain occasions )

I have aws codepipeline created with source -> set to bitbucket repo.
my webhook gets triggered on code change and aws codepipeline runs.

recently , when a code change was pushed on bitbucket repo.

webhook didn't trigger an aws codepipeline.

How I solved it.
-> I clicked on the release change ( to start pipeline )
After that it automatically triggers pipeline on code change.

Problems:
-> Why did pipeline not get triggered on code change?
-> Does this happen frequently and How to solve it?

No file, test, or entry point is named. Start by reproducing the Bitbucket push and AWS CodePipeline webhook flow described in the issue, then determine why the pipeline sometimes fails to trigger. Done means identifying the cause and documenting a reliable fix or workaround.

Written by the indexing model from the issue text.