Landingpage Path - Regex - GA4

Hi there,

I am trying display the number of sessions (GA4) that
-have the traffic source "organic search" and
-where the landingpage path matches a regular Expression

With GA3 it worked well. In GA4 it works too with a simple regex, but not for a longer regex.

I am using this regex to match Product URLs of an ecommerce Website:

((.)-[bl0-9][0-9]{5,7}|(. )-[a-z]{2,3}[0-9]{3,4}.*)

It works well when I test it to match product URLs (e.g., "/terrassendiele-douglasie-711526"), but when I try to use it in a formula, it returns the total number of all sessions, rather than just the ones that match the pattern. The formula:

=@Dump(Connector("GoogleAnalytics.BuildReport";"XXXXX";"sessions";;;"sessionDefaultChannelGroup==organic search;landingPagePlusQueryString=~((.)-[bl0-9][0-9]{5,7}|(.)-[a-z]{2,3}[0-9]{3,4}.*)";;K15;K16;TRUE;FALSE;1000))

For your reference, a different regex pattern works perfectly with the same formula. When I use this more simple Regex to filter Magazine-Articles, it works well (with the same formula):

Does someone know how I could fix it?

Since the regex is not displayed correctly in the forum, here is the message in Google Docs:

Thank you in advance!

Difficult to say, I would guess it has something to do with the regex pattern. The connector doesn't do anything with it, only sending to GA API. Perhaps it's related to this space?