In desktop, this works: https://en.wikipedia.org/w/index.php?title=Special:Contributions&target=PrimeHunter
Clicking "Mobile view" gives https://en.m.wikipedia.org/w/index.php?title=Special:Contributions&target=PrimeHunter
&target=PrimeHunter is ignored. It produces the same error message as https://en.m.wikipedia.org/w/index.php?title=Special:Contributions :
"Bad username given
Cannot look for contributions without a user or with a user that does not exist."
https://en.m.wikipedia.org/wiki/Special:Contributions/PrimeHunter works.
I don't know whether any default MediaWiki features generate url's with Special:Contributions&target=
I got the url from a gadget https://en.wikipedia.org/wiki/Wikipedia:Tools/Navigation_popups
The url form is documented without mentioning mobile at https://www.mediawiki.org/wiki/Help:User_contributions#URLs_and_links
An enwiki search of "Special:Contributions&target=" currently gives 26,466 results:
https://en.wikipedia.org/w/index.php?search=insource%3A"Special%3AContributions%26target%3D"&title=Special:Search&profile=all&fulltext=1