Hello Hector Vera,
After contacting Sony prime support, I got a telephone call this morning from them.
I explained as best I could that the hours meter had a mind of its own and decided to add on an extra hour or two 🙂
He was a really nice man and like you, he never heard of this odd curiosity before.
He suggested to upgrade the firmware to the latest v6.01. I had v5 installed BTW.
I had also noticed the date/time had changed back to 2018.
So, I’ll leave it a few days without a battery pack attached, like before and see what happens 🙂
Thanks.