When removing a gift an error is thrown.

[1c916c388a6f60e87e654891] /index.php?title=Special:RemoveGift&gift_id=10 Error from line 86 of /var/www/html/extensions/SocialProfile/UserGifts/SpecialRemoveGift.php: Call to a member function addHTML() on string

Backtrace:

#0 /var/www/html/includes/specialpage/SpecialPage.php(522): RemoveGift->execute(NULL)
#1 /var/www/html/includes/specialpage/SpecialPageFactory.php(578): SpecialPage->run(NULL)
#2 /var/www/html/includes/MediaWiki.php(287): SpecialPageFactory::executePath(Title, RequestContext)
#3 /var/www/html/includes/MediaWiki.php(851): MediaWiki->performRequest()
#4 /var/www/html/includes/MediaWiki.php(523): MediaWiki->main()
#5 /var/www/html/index.php(43): MediaWiki->run()
#6 {main}

To reproduce:
Install PHP 7.1 and MediaWiki 1.30
Install SocialProfile
Create a main account and a test account.
Make sure the accounts have each other added as friends
Send a gift from the test account to the main account.
From the main account try to remove the gift
It fails with the above error.

Environment
PHP 7.1
MediaWiki 1.30
SocialProfile at latest commit on master branch.