For me, this issue started to happen after upgrading to "Camera for OBS" ver. 3.02 earlier this week. The developer of the app has indicated that they were able to replicate the issue and they are working on a fix. I will await their fix, hopefully in the next few days. Otherwise we have had good results with the app and OBS Studio since purchasing in April.
I tried their newer iOS app, "Telecast Camera" (which works with OBS Studio, Streamlabs OBS and other programs in the Mac world), and it didn't have the issue as far as I could tell from my brief testing. You also have to download their MacOS app "Telecast Camera". However, to use the professional version of their iOS app requires another purchase (annual fee), though it seems potentially more versatile. The trial version is free.