Specifically the issue occurs with 'Match case' toggle turned off. The search box then considers queries abc\d{5} and abc\D{5} to be the same query and just pulls the previous search results from the cache.

Desired behaviour:
Search respects 'Don't Match Case' option for the regular letters, but still correctly identifies special characters (like 'digit'/'not digit' in this particular example) and interprets abc\D{5} as a distinct query.

Useful extra information
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> Klogg version 20.12.0.813 (built on 2020-12-24 from commit 576b91d) [built for x86_64-little_endian-llp64]
> running on Windows 10 Version 2009 (winnt/10.0.19043) [x86_64]
> and Qt 5.15.2