GarageBand on M4 iPad Pro exports distorted audio files using Apple Lossless format

Using M4 iPad Pro running 18.2.1

Running latest GarageBand version 2.3.17, updated Jan 15

To reproduce:

1. Use GarageBand to record a simple narration, using internal or external microphone.
2. Save the file to local storage as usual
3. Use the Select function to Share just one recorded file
4. Select "Share Song" format
5. Select "Apple Lossless" audio format
6. Use AirDrop to transfer to any Mac
7. After the file appears in Downloads on the Mac, open it with QuickTime Player.
8. Note that the voice in the narration is horribly distorted - completely unusable.

Fortunately I have a second iPad Pro - which is 4th generation and therefore pre-M processor

Using the exact same procedure with GarageBand, I have successfully exported around 100 songs to a Mac for use in FinalCut Pro or iMovie.

Why does my new iPad Pro with M4 chip have such problems with GarageBand? When I first got it with an early 18.x version, I couldn't even record a microphone successfully. iPadOS 18.2.1 at least allows me to record, but in order to export I have to go back to my 4th gen iPad Pro.

Does anyone else have this problem? A search here did not turn up anything.