Dealership changing given modules in HV pack without informing owner

I have a 2005 with 140k miles. Bought it used a little over a year ago.

ABS actuator, front-rear brakes, 12V battery, regular water pump needed changing.
The inverter coolant pump was changed via the recall.

The car started its journey in Denmark where it was only first registered in 2008. It must have been a saloon car. Then it was exported into the Netherlands from where in 2014 I believe was exported to Hungary, where I bought it from the first owner.

Since its was first registered in 2008, it still had the hybrid battery warranty until 2019 May period. And here is the kicker.

I had the bus bars changed as maintenance in an independent hybrid shop in 2019 June and we saw something very strange. There were marks on some of the modules of the HV pack, indicating, some of them were changed. But how could that be, if there was a live warranty for the pack at the time?

The pack was not brand new that would indicate a complete pack change by Toyota.

I know the previous owner did not do anything to it and he had been doing the yearly HV battery warranty check for the car at the dealership, to get the yearly warranty for the pack until the car's 10th year of registration that ended in 2019 May.

The independent shop owner said that Toyota themselves could be changing given modules that might fail in the near future based on the voltages at the yearly checks, in order to keep up the great PR of hybrids. In general, the packs might fail before 10 years that would in general hurt their PR. But that's just a theory.

Has anybody heard, experienced something similar?