It is possible to attempt to favourite a pipeline that is unfavouritable.

Steps to Reproduce

1. create a new git pipeline from a git repo with no Jenkinsfiles ( https://github.com/jtnord/maven-test-project.git )
2. go to the pipeline page and reload (workaround existing bug)
3. click on the star to auto favourite the pipeline

expected results

1. the pipeline will be marked as favourited and as such any existing and future branch will be a favourite on your dashboard
   or
2. the star is greyed out indicating you can not perform the action

actual results

1. you get an error a couple of seconds later

Video showing the issue