Since a while the UI in "Configure System" area was broken, not really sure when this issue started exactly to occur, but after some debugging we saw that the plugin Performance Signature: Dynatrace AppMon 3.1.6 was causing it, except the UI is broken also the "Apply" and "Save" button do not work. No Errors in the logs produced by this. Removing the plugin fixes the issue.  We use Jenkins 2.284.

Attached the screenshots how the UI looks and the empty error popup after clicking the apply button.