CLR unloaded due to security data definition language

Today, we got a very weird situation. We added a SQL login to our database server. After adding this login, SQL unloaded a critical CLR routine "due to security data definition language" (error 10310). As a result several user processed crashed. The CLRs unloaded in all the registered databases, but the new login had nothing to do with these databases. The databases using the CLR have the TRUSTWORTHY setting to on. Any idea why creating a regular SQL login is causing this issue? It's certainly NOT a memory issue, plenty of GB available for the OS. We fixed this issue by executing TRUSTWORTHY and registering the CLR, but we're a little afraid if this happens again when adding another login. Configuration: SQL server 2019 CU20 Enterprise, 512GB memory, 384GB for SQL