happened more then twice to me:
when the battery is empty so the camera turns off it forgets WB and REC SET parameters,
so I had to reconfigure after the battery replaced. happened both on genuine and aftermarket batteries.
annoying when in a rush.

How quickly after the camera shut down did you change the battery? Do you get the same problem if you swap batteries before the first one is fully discharged?

last time it was a minute or so between the camera shut down
and the battery change since the spare battery was in another room.
taking out a charged battery when the camera is on doesn't led to reset.
AFAIR there always was a "low battery" warning before the settings reset.

I was filming some wedding speeches yesterday & I had to change one of my batteries before the end, My camera's WB, Iris, SS & Gain all reset to auto & the manual WB lost it's previous value when the new battery was inserted.

Unfortunately I think it's just a camera 'feature'

Now in holiday so my user manual is out of reach
AFAIR mostra of the user settings can be sent to the SD (to be shared with other camera): am I wrong?
If it is true, one can memorise its own settings and recall after unexpected reset.
Plese correct me if I am wrong

Paul, this is exctly the case.
if this ia a 'feature' why I'm not able to reproduce it twice in a row?

Sauro, you are right about saving settings to the memory card,
but in most cases the camera is not resetting, so this yet to become a habit.