Mindswap is still a mess
Created by: ghost
Mindswapping causes your spells to only produce the spell chat lines like "ARSE NATH" but doesn't actually cast the spell. This was with having robeless spell and trying to cast knock/arsenath after mindswap.
According to thread it also gives your victims your spells.
Related https://github.com/d3athrow/vgstation13/issues/4836
Regardless of what the fluff description says, mindswap never did or should have caused spells to be forgotten or unusable, as that makes it absolutely pointless combined with the obvious mechanics giving away that a mindswap is in progress.