Cache Discovery | Plugin does not exist. Valid plugin IDs for....

As a bug can we get a failing test showing this issue

Thanks.

Writing a test for this can get complicated quickly (at least for me). I gave it a good try, but I could not find a way to dynamically define a new plugin definition that could simulate a new deployment while triggering the cache on simulated "old" code without this plugin.

Regarding the bug itself:
It may be more likely to appear when a new plugin definition is written in an already enabled module. The ModuleInstaller.php does invoke plugin.cache_clearer > clearCachedDefinitions, making the window where old cache discovery can be triggered much smaller.