Thanks for reporting this, @hseverac , and welcome to the forum.
In the recent update I did change how PopClip opens tabs in Safari. This was done to solve a different problem regarding tab groups, and also to allow background tab opening (when holding Shift).
It looks like this issue with Spaces didn’t get flushed out during testing. I’ll investigate, and report back here.
In the mean time you might wish to temporarily install the previous version of PopClip.