I was looking for an update on this issue in the following topic:
https://together.bunq.com/d/38904-reported-battery-problem-very-high-usage-in-the-background/76
But to my surprise it was closed without a fix. It doesn't make sense to blame this on Samsung devices when there are multiple people having the same problem using different devices. Also the only app that causes this battery drain issue (out of 400 other apps) on my phone is bunq.
Regarding all the information users provided one of the most likely culprits is some infinite loop that starts which causes the CPU to max out on 100% usage.
I find it very offensive to just close the topic when the bug is still affecting multiple paying customers who are told to just deal with it. I would really like to see this issue solved.
I still have to force stop the bunq app 80% of the time after I use it even though i don't lock my phone while the app is in the foreground.