Camry XSE - engine not recharging hybrid battery anymore

Hi, I was wondering if anyone had run into a similar issue that I have been having with my 2025 Camry XSE. I have had my Camry since October 2025 and generally the hybrid battery had stayed fairly well topped up and used a pretty even mix of electric and gas motors, and I'd been getting very good gas mileage, especially on the highway.

A few weeks ago, I was using the Adaptive Cruise on the highway and going downhill when a semi decided to slow down to 50mph, causing the Cruise to brake quite hard, over-revving the engine, and going quite heavily into the Charge part of the gauge. Not wanting to strain the engine, I cancelled cruise and the revs immediately dropped back to normal. But after work, when I was driving home, I noticed the hybrid battery level quickly dropped to half charge, and then the hybrid system kept going in a cycle of trying to use the engine to charge the battery, the charge not going up, it would quit trying to charge and then do brief little blips of electric motor usage, and the back to trying to charge the battery. It would barely use the electric motors because the charge was at half. And my gas mileage when I stopped at home was 37 mpg, on a route I would typically get 42-26 mpg.

It seems to me like something in one of the motor generators has broken and is no longer sending charge to the battery from the engine. The only time the battery level goes up anymore is when coasting or braking. Even sitting idle, when the engine should be easily able to charge the battery, the gauge never goes up. And I swear, I use to see it go up all the time when the engine was charging it.

I took the Camry to my local Toyota dealer, but because the car was not showing any error codes, the technician said it was behaving normally. He even told me that the engine wasn't used to charge the hybrid battery, only coasting and braking. But I swear before the incident with the semi, that the battery always stayed pretty well charged and my mpg were much better. And I remember seeing the battery gauge actively go up when the engine was sending charge to it. Am I just crazy, or could something be wrong with the charging system without sending an error code?