Hi @alxnzx, based on your screenshot it’s unfortunately hard to say what exactly is happening. Perhaps you can share an example workflow including some dummy data using which your problem can be reproduced?
My first guess is that your sourceSwitch node returns a different number of items than your versionFilter node receives. So you might need to use an expression like {{ $("sourceSwitch").first().json.yourRegexField }} to always use the first field from your sourceSwitch node for the comparison, similar to what I described over here.