Hi,

anyone have had any such problems that device is charging to 100% but when switched off and turned on again, it will show only 67% of battery remaining? Tested this several times but result is still same. Using original charger and cable. Any kind of battery calibration needed to do? 
Android version 8.0.0

It looks like a battery or charging board related issue. Before looking for an hardware issue, it's highly recommend to perform a factory reset (= total wipe!) from the recovery menu as showed here:

viewtopic.php?f=192&t=334922

Perform a factory reset, then, when prompted to, don't load any previous phone backup, just start from scratch. Let me know if something changes.

Followed the instructions and did reset for the device. Even with "new device" option, after charging it 100% and turning it off, battery still showed 67% after turning on. 

Ok, that's definitely an hardware fault.

You'll have to replace the charging board and the battery. This won't cost much

https://m.it.aliexpress.com/wholesale/b ... gclid=null
https://m.it.aliexpress.com/wholesale/B ... ro+battery