Summary:
After upgrading to Jenkins version 2.504.2 and updating all plugins, our Bitbucket-to-Jenkins webhook integration (using the Bitbucket Branch Source plugin) stopped working.

Details:
Before the upgrade, we had the Bitbucket Branch Source Plugin version 936.1.1 installed. Everything worked as expected. After the update, webhook notifications from Bitbucket are no longer triggering builds in Jenkins.

Bitbucket Configuration:
In the Bitbucket repository under Workflow → Post Webhooks, the incoming webhook URL is set to:
https://MYJENKINS/bitbucket-scmsource-hook/notify
(Note: MYJENKINS is a placeholder for the actual Jenkins instance URL.)

Notification settings and final steps are configured correctly and have not changed.

Jenkins Configuration:
Under Manage Jenkins → Configure System → Bitbucket Endpoints, we have a valid configuration:

• Server URL
• Server Version
• "Call changes API" enabled
• "Manage hooks" enabled
• Valid credentials

The "Webhook implementation to use" is set to Native. I have also tested with Plugin, but that did not work either.

Observations:
When pushing a commit to Bitbucket, the following log entry appears in Jenkins:

INFO c.c.j.p.b.h.BitbucketSCMSourcePushHookReceiver#doNotify: 
No bitbucket endpoint found for https://bitbucket.org to verify the signature of incoming webhook.

It seems like Jenkins is unable to match the incoming webhook to the configured Bitbucket endpoint, even though everything appears to be set up correctly.

Expected Behavior:
Webhook triggers from Bitbucket should be received and processed by Jenkins, triggering the appropriate jobs.

Actual Behavior:
Webhook is received but rejected or ignored with the message above, and no jobs are triggered.

Additional Notes:

• We are using Bitbucket Server (on-prem)
• This issue only started after the Jenkins core and plugin updates.
• The configuration worked flawlessly before the upgrade.