The binary release for iOS is not built for distribution, this causes the new Swift compile (5.3) from XCode 12 unable to import the released binary (which was compiled with Swift 5.1.2)
To fix it please refer to the following StackOverflow question.
https://stackoverflow.com/questions/58654714/module-compiled-with-swift-5-1-cannot-be-imported-by-the-swift-5-1-2-compiler/58656323#58656323