Version 0.1.1-4 of pandoc-plantuml-filter is marked for autoremoval from testing on Tue 04 Feb 2025. It depends (transitively) on plantuml, affected by #1039999, #1040000. You should try to prevent the removal by fixing these RC bugs.
Migration status for pandoc-plantuml-filter (0.1.1-4 to 0.1.1-5): Waiting for test results or another package, or too young (no action required now - check later)