The problem is with our detection of illegal titles - it only OK's characters up to \uFFFF (i.e. the BMP[1]), which does not include Gothic, which is in the SMP[2]. I've changed our whitelist (which whitelisted up to \uFFFF) to a blacklist in https://gerrit.wikimedia.org/r/78525 , which should fix this issue.

[1] https://en.wikipedia.org/wiki/Plane_(Unicode)#Basic_Multilingual_Plane

[2] https://en.wikipedia.org/wiki/Plane_(Unicode)#Supplementary_Multilingual_Plane

Best,

Merlijn