Jin Choi 

I can repro issue #1 even in Trados Studio 2022 & 2024. It’s an old bug, isn’t it  Paul ?

About issue #2, if you want to use backreferences, you need to use “$1” instead, and this works. Having demonstrated that the Replace with field uses regular expressions, it won’t handle properly the pattern “$1 \(”, while “$1 (” will be handled as a hybrid pattern (a backreference followed by a non-regex pattern), which puzzles me… Paul ?

Thank you so much! "$1" works. You are my lifesaver.

 Jin Choi Jesús Prieto 

Jesús Prieto said:

It’s an old bug, isn’t it  Paul ?

Yes... our reference CRQ-10543.  It's such a rare thing it's never made it to a fix.  The main reason it's rare is that this only occurs if you specifically check the regex checkbox first and then uncheck it.  If you didn't do this it works OK.  And of course using regex is an easy workaround.  So never made it to be prioritised over other things.

Jesús Prieto said:

Having demonstrated that the Replace with field uses regular expressions, it won’t handle properly the pattern “$1 \(”, while “$1 (” will be handled as a hybrid pattern (a backreference followed by a non-regex pattern), which puzzles me… Paul ?

Probably because using any regex apart from a back reference in the replace field would be incorrect.  The replacement only uses literal text.  So I would expect this:

$1 \(

To replace with the captured back reference followed by a space and the literal characters \(.  Which does work.