If you've checked for any updates and this is reproducible, then it would appear to be a bug related to the new desktop.
I did a search of the reported bugs in R2025a/b for various keywords such as 'xlabel' and found none; I would suggest it would be worth going ahead with a bug report; Mathworks may not be aware of nits such as this unless somebody discoverrs and reports it -- if it has been reported or is in an internal database, no harm done.
One Mathworks staffer who frequents the forum noted not terribly long ago that he has been surprised to find that seemingly obvious things actually were not in the database yet even though there were sometimes multiple forum reports because nobody ever did file the formal bug report.
