Invalid CSRF token errors on multilingual sites

Problem/Motivation

On multilingual sites with language prefixes used, the ajax requests with CSRF tokens are failing with this error response:

{"status":"error","message":"Invalid CSRF token.","ticket_id":"WA-692714294fa77"}

The error log shows these details:

CSRF Fail: Token=kQfj28QjLczNWbl82W6zhJUI51yu_O521mRBYbwB064, Path=de/wa/register/options, Valid1=NO, Valid2=NO (Ticket ID: WA-692714294fa77)

So, it called the path de/wa/register/options. If I manually correct this to not use the language prefix, it works. So it should call the path wa/register/options instead.