Why the music doesn't working after phone calls on headset?

[CreaterNo1]

Hello Everyone,
I have a problem with my phone for a long time now.
The situation is the following:
1. - Someone calles me.
2. - I reject the phone call
2.1. - (The music is still working here if I start one)
3. I recall the person who called me.
4. Phone call finished.
5. Trying to start a music with headset connected.
6. No sound at all on headset, but there is with speaker of phone.

Phone details:
Model: Sony Xperia Z2 - D6503
Android: 6.0.1
ROM: Mx ROM V8.6.0 cc (The reason why there is a custom ROM on the phone because it didn't work with the original either)

The headset doesn't matter, because it do the same with every headset, but just in case if that would help:
Sennheiser CX 5.00g

If you need any information regardign the issue I will answer with my best knowledge.

 

[CreaterNo1]

I still have this issue. A reboot solves it, but it is a pain to do that every time.
I've discovered that if I don't play music when someone calls me, it will be okay.