Warning: Title::newFromTitle: $text must be a string
from
OutputPage->addTemplate/QuickTemplate->getHTML/CollectionSuggestTemplate->execute/CollectionSuggestTemplate->getProposalList/Title::newFromText
Seems to be a recent regression.
Note that Title::newFromText already throws for objects and tolerates null. So this must be a primitive non-null, non-string value being passed somehow.