Several users are reporting on pt.wiki a bug that is exactly the same as https://bugzilla.wikimedia.org/show_bug.cgi?id=70415 (as it is currently closed, I am entering a new bug, sorry if this duplicate is incorrect).
We can easily reproduce the problem trying to link [[:pt:Flodoardo]] to [[:en:Flodoard]] on ptwiki. The users experiencing the problem says that it is possible to workaround the problem linking the pages on the other side (going to Wikidata or en.wiki to add such link).
Users report (in portuguese):
Version: unspecified
Severity: major