Sadly It doesn’t come as a complete surprise to me. About 2 years ago using Firefox Focus on iOS I came across an odd behavior - each time I launched the app it was accessing and reading the device’s clipboard.
I called it out to Mozilla both through the app review and Mozilla support. The only response I got was that it was a feature. That I misunderstood what they were attempting to do. They removed that “feature” in the following version.