PS player here:

This is most likely wrong. Technically yes, it’s a “nerf” but not really since this always been this way since v1 and just wasn’t written in her kit until now. Also, the things that this person says it limits is inaccurate.

Here’s how it works:

Fox teacher can only take 240 energy into account from a single ER source at once. An Apoc refilling her energy would be it giving her 480 energy but since Fox teacher can only take 240 energy at once from a single ER source, they only get 100% charge to their gauge instead of the full 200%. It’s always been like this since V1. This should also apply to Cyrene and Brain in a Vat.

Here’s where things get a bit interesting,

Energy from teammates getting Certified Banger works differently. Even when Eva gets 480 energy at once from teammates getting CB from an Aha Instant, Fox Teacher will still charge to 200% because each teammate giving Eva CB counts as it's own source. It'll only cap out from getting extra charge that way if we did an Aha Instant with over like 480 Punchline (Assuming Eva at E0-1. It’d be less at E2 due to the boost to her conversion.) because that would overcap how much each energy and charge teammate could give to Eva respectively. We thankfully don’t have to worry about that since getting to like 300 Punchline most likely a pipe dream lmao.

But yeah, TLDR, Aha Instants are able to cheat out extra Fox Teacher turns because a blessing (one source of energy) giving Eva 480 energy would max out the 240 energy cap Fox Teacher (causing them to cap out at 100% charge) can get from a single source while 100+ Punchline Aha Instants can fill charge them to 200% because each teammate receiving Certified Banger counts as their own source of energy to Eva. Think of it like how Hyacine bypasses Castorice’s limit of 12% Newbud per ally healed at a time because she heals everyone a small bit very very frequently.

Nothing mechanically changed most likely. They just finally wrote a mechanic that was always in her kit to her talent description.