TLDR:
Has anyone had a problem with an R5 camera body draining an LP-E6NH battery while turned to "off"?

Context:
A couple of times now, I've pulled my R5 out of my camera bag only to find the OEM battery that shipped with the camera body completely drained. 

The first time this happened I was in a hurry to get a shot so I just grabbed a LP-E6N battery out of my R (which had been sitting unused longer but has never had this issue) and carried on shooting. I assumed I had accidentally left the R5 switched to "on" in my bag, took myself to task and made sure I started turning it to "off" after use.

However it has now happened again, and the camera was definitely "off" and was definitley near full when I put it in my bag. It had set about 10 days between usage. This time I had a backup OEM LP-E6NH which I had charged at the same time as the LP-E6NH that was now dead in the camera. That backup battery was still full. 

I am still not sure if I have a bad battery or a camera issue, so I am starting to try and isolate variables, starting with leaving the second OEM battery in the camera unused for a few days to see if it drains. I'm open to other suggestions, but has anyone had a problem with an R5 camera body draining an LP-E6NH battery while turned to "off"?