Why the Phones are locked on PCMA insted of g722

It does not make sense.
before i upgrated to latest pbxversion, it was working fine
in general sip setiings, i have only checked g722 codec.
after restart the phone its still on g722
i tried to uncheck all the codec - i expect that the phones will not be able to communicate, but i see it locks on pcma again.
how i can debug this?