Changing camera to back camera cause camera to be black and white

We have a jitsi-based video conference android app and We have received report from one user that when He change camera from front camera to back camera, camera gets black and white. One of his family with same phone model face the same problem.
The phone is Huawei Y6p and user faces same problem on both jitsi and our app. But they have no problem on other apps.
Can anyone help us to solve this problem?

Please don’t tag people on posts unless they’re already helping you with the issue.

This sounds like a phone-specific problem. When you say “other apps”, do you mean other webrtc apps?

Thanks for your advice.
We have checked whatsapp call and camera app yet.