There are 38 specs in the game but API calls to /data/wow/talent-tree/index only returns 33 specs. It was properly returning 38 prior to 10.1 rolling out last Tuesday but is now missing five trees (making it impossible to programmatically get the full trees for those specs).
This endpoint had previously regressed similarly earlier in the year but was eventually fixed after a month or so - hopefully this endpoint could get shored up so this doesn’t keep happening.