Steps to reproduce the issue

Pick-up the API-Token and you can use the attached scripts with curl commands.
Or try by your own to delete not-trashed tag, category and article via API.

Expected result

An approbiate HTTP status code like 409 "Conflict".
And an error message like: Tag/Category/Article must be trashed before it can be deleted.

Actual result

HTTP status code 500 and error message "Internal server error".

System information (as much as possible)

Found in testing #44670, Reproduced in Joomla 5.3.1, see bash scripts and output:

• api_500_test.sh.txt
• api_500_test.log

Additional comments

• Only tags, categories and articles were tested. It is expected that more entities will be affected.
• Is it possible to extend the System Tests for this issue? You could do TDD and write the tests first. 😄
• This may be of low priority as it is only an incorrect error code and the cause of the error is missing.