Voice memos from Android coming through as .mp4 instead of playable audio

When Apple first allowed voice memos to be sent between iPhone and Android users, everything worked fine and behaved similarly to WhatsApp voice notes. I could tap play directly in Messages and listen normally.

For the past few months, that’s changed. Now when an Android user sends me a voice memo, it arrives as a file named something like “Recording0000.mp4.” Instead of a play button, I have to tap the file and it opens like a video, even though it’s only audio.

This has become inconvenient because if my phone locks while the audio is playing, it stops and I have to reopen the file and start over. My friend who also exchanges voice memos with an Android user does not have this issue and receives them as normal playable audio.

Has anyone experienced this or know why the format changed and how to fix it?