It looks like this could have been a problem even with the old label? If I change the text to wikibase-save from nl.json, it looks like this:
But perhaps my font setup is different and on your system that used to fit?
I've tested it too (and didn't need to change nl.json, but only edit the text in the browser inspector)
For my screen the current situation just fits and the old situation had some spare space to the right.
and didn't need to change nl.json, but only edit the text in the browser inspector
that’s what I did as well, I just meant – I don’t speak Dutch, so I had to look up the Dutch translation of “save” in nl.json :)