Monterey 12.3 on a macbook M1 13 inch and still happening. Tried all of these possible work arounds here and nothing works reliably for me. Each one creates another unique set of issues, but no actual fix for me. My least hassle work around is time machine backup into my thrunderbolt dock directly (no extra hub), enable put hard drive to sleep when possible, disable wake for network access. disable prevent mac from automatically sleeping... My backup hangs up every now and then and doesn't shut down when it should with the rest of the computer, especially sleeping for long periods like overnight. But I have less of the improper eject messages and the backup never leaves my desktop now and stays accessible. This is all Very frustrating...