At the bottom of that diff you can see I copypasted some text between <small>near other words which were already small, causing <small> tags galore (it reminded me of bug 52189, except there's of course no button in the interface to set text size yet) - Win7, Chrome.
NicoV noticed it in this diff https://fr.wikipedia.org/w/index.php?title=Le_Flingueur_%28film%2C_2011%29&diff=103613466&oldid=103204882 which BTW features more disruption which may or may not need to be filed separately (in case, let me know); he reproduced the extra smalling thing, and has my same setup.
Version: unspecified
Severity: normal
URL: https://fr.wikipedia.org/w/index.php?title=Utilisateur%3AElitre_%28WMF%29%2FProve2&action=historysubmit&diff=104054074&oldid=104054034