I have not experienced that on my Enduro 2 17.28. My watch holds battery very, very well in fact.

Do you still experience this issue? If so I'm thinking you must have GPS activated permanently? 

Try the Troubleshooting guide for high battery drain 

I have the same issue with my Enduro 2 on 18.14

I noticed the same issue with my Enduro 2, currently on 18.14. From 100% to 84% battery in 6 hours with no activities.

Update to a new version fixed this problem

I don't remember exactly what version that goes after, sorry. Now I use 18.14

So you saying that 18.14 fix your battery drain? Cause me and many users here disaggree

I didn't say that is the fix. I said that the problem with the battery drain was gone after updating to the next version on my device.

Which version fixed your problem? I’m on 18.14 and in less than 24h I’m at 55% from full charge with no activities