I've burned some backup BD-R for demo purposes (I do have the originals). From the 20 I burned, only about 5 still plays. The rest will show up as "BD-R BDMV" - "CAN'T PLAY" on my BDP-05, BDP-51 and BDP-23.

Any clue why suddenly some titles can't play although some other titles still can play without a hitch? They were all burned using the same media brand of the same spindle within the same month using the same burner.