As was mentioned in MCPE-40274, if you try to import a behavior pack containing mcfunction files, but do not specify a min_engine_version, then when you try to execute the function you get an error saying that the min_engine_version is needed. Okay

But when you add a key/value pair for min_engine_version to the manifest.json, then the behavior pack no longer completes its importing on the iOS build of bedrock edition 1.8.0.

Please find attached an example of this — an mcpack which I believe is entirely valid, and which defines a single function, but which does not import.

I’m adding the min_engine_version key/value pair as specified in https://minecraft.gamepedia.com/Function_(Bedrock)