Hi Tony,
thanks for keeping track on this!
Indeed, the solution was found a couple minutes ago, after I scared up all people (technicians or not) involved in the project and was supported by them in looking for the error. After we made a fresh install of the same lime survey version and I stared to adapt the survey, I found the error. And I can't belive that I was that dumb! I totally forgot about the only thing next to $showsgqacode I changed in the php files:
I added $_GET = 99184; in the beginning of index.php to always forward visitors of the server root to the only survey, skipping the Welcome page. That worked out pretty nicely, and I didn't notice the faulty behaviour quite some time. Then, I couldn't connect it to that change...
So, it's resolved now! THANK YOU TONY for reproducing the non-error!
The only thing left is to find a new way to set the default survey. But I will make a new topic for this, as I can imagine that others might be interested in that, too.
All the best
Jonsen
P.S.: You can "cash in" beers and bed&breakfast any time