Facebook call on Samsung galaxy a 10.1 Tablet uses call volume (and not media volume)

[AC Question]

Hi everyone,
I am experiencing some problems with my galaxy tab a 10.1 with Android 6.
Whenever I do Facebook or skype calls, the system selects automatically call volume even if there is no "phone speaker" just loud speakers! In this way the volume is really low even when cranked up to the max.

Any idea on how to convince the system to switch to media volume for skype and facebook calls?

Thanks!

Giacomo