Why is an encrypted APFS volume mounted with no password provided vulnerabilities?

Environment:

  • Apple M3
  • macOS Sequoia Version 15.5 (24F74)

Problems: I find Disk Utility does not require password to mount an Encrypted APFS volume after I force eject the encrypted APFS volume.

As shown below, store2 is an encrypted APFS volume:

enter image description here

After I force unmount it. The token grey out.

enter image description here

Then I mount store2 again. This time no password is required (it should require password to decrypt it.).

Does anyone know what mistake going on here and how to fix it.