I'm posting here because I think that my case has some similarities: After last update of Evernote on my android (HTC Desire HD) I have strange behavior with SD Card:
Often I got the message that SD card is mounted read only, after which I must sync all notes from scratch. Sync finish successfully but it does not lasts for long. After while I get the same message for SD card.
Sometimes after sync finishes content of notes is real mess: only bunch of some strange characters. Sometimes it's ok.
I've reinstalled evernote few times (with phone reboot). Also I've scanned/repaired the SD card on Win7 (as soon as I insert the card, Win 7 offers to check and repair), deleted evernote folder on it prior evernote installation and syncing.. .
I don't claim that SD Card is 100% ok, but I suspect that has something to do with last update. Prior that evernote was functioning excellent ... and I was very happy EN user .