free set equalizer not working with AUX connected audio devices = using it as a mp3 player

[woswasi]

z1 & x compact no problems, equaliser is always working

but we do have two XA2 phone
really happy with the phone (5th sony mobile in total)
but there is a very annoying fail:

for about 6 months now, the equaliser doesnt work always

x) it works fine with any headphones.

x) it does NOT work with audio devices, which are connected with cable over the AUX 
if you connect the cable you hear a scan, sounding like "ts ts ts ts ts" then the equaliser is deactivated

1) mercedes a calss radio 2) hifi in the workshop 3) hifi at home
with both xa2 phones

it occured about 6 months ago, something was changed

its a software issue, not a hardware problem

1) scan is started as soon as you connect something to AUX
2) decision taken to deactivate the eq
why?

the x compact does not scan btw.
(z1 is long gone, never had a problem)

its important for me to use it as a mp3 player ever since

the german sony support over mail gave up, they dont know (??!??)

someone does for sure know 
lets find her/him over here

[woswasi]

its pretty interesting and also sad that the german sony support
insist on not being able to help. they dont know. 
and i shall use the developer page (sure, as i clearlly want to develop something...)

there is no answer why old phones do not have these problems
why something was changed recently and what the decision
- to turn a software off, after a hardware scan - is based on.

[woswasi]

new support replied who tries to really help 

bug still exists with android 9

developers are informed

= work in progress.