When some of the editors on se.wikimedia.org have been editing pages non-standard whitespace characters (possibly nbsp characters) have been introduced onto the pages, sometimes replacing pre-existing space characters. This has caused issues since it can break templates (see T249646).
This occurs both on desktop (Chrome on Ubuntu) and on mobile (**?** on Android) and both on page creation or editing a pre-existing page. It also happens both when the added content has been copy-pasted from somewhere else or manually entered (e.g. `~~~~`). It seems to only happen when templates are edited, but that might be an observation which is biased by this breaking templates whereas the change might go unnoticed in other contexts.
While the exact source of this is not clear it does not seem to be due to the editor used since there are edits tagged as `visualeditor-wikitext` introducing these, but also edits done using the '2010 wikitext editor'.
Examples:
* Exemple edits where such whitespace is introduced:
** https://se.wikimedia.org/w/index.php?title=Projekt:En_gemenskap_f%C3%B6r_alla_2020/Projektdata&diff=prev&oldid=81764&diffmode=source
** https://se.wikimedia.org/w/index.php?title=Projekt:FindingGLAMs_2018/Resebeslut_Offsite_Berlin_Andr%C3%A9&type=revision&diff=78364&oldid=78362&diffmode=source
* An edit where such whitespace is fixed: https://se.wikimedia.org/w/index.php?title=Projekt:FindingGLAMs_2018/Resebeslut_Estland_Axel&diff=next&oldid=78093&diffmode=source