It was due to something being changed but it only affected certain things so... You wouldn't just roll it back and you'd also want to make sure the new changes don't 'also' cause issues. Asides, they seem to be working on finding a good balance for her which might mean adjusting some of the base values like Mech health, Mech's melee damage and such. Considering some people are actually doing 'very' well with her it's hard to definitively say she needs major adjustments. Already encountered two players doing quite well with Aneska but alas they are what one might consider pros in the game.
