Unable to save hotkey bindings across game sessions

[x08fd]

Using PI 3 B+ DragonBlaze
Internal storage only.

I'd like to use hotkey+L to save, and hotkey+R to load. Here is what I observed:
After entering the game and toggle the menu, I'm able to change hotkey bindings. Resume the game and play with new key bindings, no problem.

After quitting the game and start a new one, the settings are lost.

I've made sure to turn on the option to "save settings after exit".

Also noticing this:
I was able to see the files on a computer with network sharing. The retroarchcustom.cfg DOES get updated after I change the settings in a game. But it's reverted to default settings after quitting and starting another game. Not sure if this would help.