Loud speaker stop working when increase the volume

I have iPhone the loud speaker will stop working if I increase the volume above 50% on all application. Then I need to reduce the volume and access the app again, same apply for the ring tone.

I changed the loud speaker with a new one and even the doc connector, I installed a new one still the same issue.

the small speaker works fine so I don’t think it audio IC.

I did reset for all setting and installed the latest iOS version.

Any one had similar case, since I have been searching for the past 2 day and didn’t find similar case.

thanks