@raphael-bueno-hatencia Please, don't SPAM:
@zing Yes, after each test, I did a factory reset from menu.
Thanks to your link I found something that changes on \SHARE\system.emulationstation\es_input.cfg
I realized that after configuring correctly:
This was changed on es_input.cfg:
The solution was change the values of L2/R2 from before the controller config. Restart and Kodi stop muting when pressing L2.
Don't know why configuring changes those values, I did it many times so I'm sure I pressed the correct buttons every time.
Thanks a lot @zing for the patience and helping me. I hope this helps anyone with this problem too.
I am having a similar issue. I am currently dealing with other issues, and hope to write a script to correct this issue as a kludge, but it would be nice if someone could help determine why it is happening in general.