I'm using the official balanced card that came with my 901s.  Hmm it sounds like it could be this amp card causing this?  Have you tried whether your battery drains in shutdown with the balanced card installed?

Thanks Zniper. Looks like I should ask for a replacement unit.

My 1-month old HM901s seems to have a problem with properly shutting down (after going through Settings->Power Off->Yes, not just entering sleep mode).  The problem exists with both firmware version 2.003 and 2.004.   For example, I charged the battery overnight and checked this morning to...