Neato XV Signature Pro battery calibration procedure

I am now doing the procedure explained on this page

https://www.neatorobotics.com/support/articles/recalibrating-your-neato-xv-batteries/

I pressed "New battery" and started a house cleaning according to the procedure, it cleaned normally except it still got the error message "My vision was blocked. Please press OKAY" like usual. When it needed to go back and charge, this happened.

And it never found the way back to the charging station, it kept going everywhere else except to the charger. Even if I put it right next to the charger it couldn't find it.

I am however not sure if this is part of the program, maybe it is supposed to do this to drain the battery.

Finally it shut off because the battery was drained. Then I pressed start to start a new house cleaning and it displayed “My Battery is low. I need to charge my battery before I can clean”, and I put it back on the charger. So it is according to the procedure so far. I just didn't expect it to go this crazy?

However, if it doesn't fix the "vision blocked" error, I don't know if I should buy a new battery or return it to the store. If it's going to act this crazy again, I'll probably return it.

Update:

Now it started cleaning automatically once the battery was charged. And nope, it still got a vision error. But now it is cleaning again. So I'll have to wait and see if it can find its way back this time. It is cleaning normally, it doesn't seem to be confused or anything so I don't know.

Update #2:

Now, this time it at least found its way back to the charging station.

Update #3:

It went back to the charger and I canceled house cleaning. It was late and I wanted to go to sleep. Also my father is here, he'll probably complain about it so... If I was alone I would let it finish anyway. I hope that this didn't ruin the battery cal. But I'll find out today, when it has charged over night if it runs better, without vision errors. Hmm, it could still be just a battery fault anyway. I wonder if old rechargable batteries might have problems outputting enough current. So I'm still not certain if I should just get a new battery or not. But I'll just return it if it keeps being stupid. I was so satisfied with this vacuum cleaner, it was a really good robotcleaner. This just happened so randomly. I never did anything to it that could have damaged it.