I have a dozen or so Jenkins jobs that are configured to be built from GitHub tags.  We have a GitHub Enterprise server on-prem that we use.  It was all working fine up until a couple days ago.  I have not made any config changes or upgrades to Jenkins around the time it stopped working (Jenkins was upgraded 19 days ago).

In the Jenkins job, if I view "Multibranch Pipeline Events" I can see that the webhooks are triggered, but they are not built.

[Mon Mar 02 19:49:59 GMT 2020] Received Push event for tag 0.3.5.8 in repository docker-images/echo-webserver CREATED event from 192.168.47.5 ⇒ https://jenkins.mycompany.com/github-webhook/ with timestamp Mon Mar 02 19:49:54 GMT 2020
19:50:01 Connecting to https://github.mycompany.com/api/v3 using jenkins/****** (Jenkins service account)
Examining docker-images/echo-webserver

Checking branches...

Getting remote branches...

Checking branch master

1 branches were processed

Checking pull-requests...

Getting remote pull requests...

0 pull requests were processed

Checking tags...

Getting remote tag 0.3.5.8...

Checking tag 0.3.5.8
'Jenkinsfile' found
Met criteria
No automatic build triggered for 0.3.5.8

1 tags were processed (query completed)

1 tags were processed

Finished examining docker-images/echo-webserver

[Mon Mar 02 19:50:05 GMT 2020] Push event for tag 0.3.5.8 in repository docker-images/echo-webserver CREATED event from 192.168.47.5 ⇒ https://jenkins.mycompany.com/github-webhook/ with timestamp Mon Mar 02 19:49:54 GMT 2020 processed in 5.9 sec

I have the build strategies configured to Discover Tags, as well as build tags.

How can I debug why it stopped processing tags?

An interesting note: I have a second instance of Jenkins as a dev server with the same Jenkins and plugins versions, and that instance is able to build off of tags.