Might be a protection issue, can't say for sure. Here's the facebook post I was talking about, notice the date.
Hiroyuki Nishimura Some of animation should be DRMed by request.
These animations don't be buffered.
So you need enough speed of internet...
August 12 at 10:01pm
So, this has been an issue with them for a while. This was a reply about the Twin Angel, Dark Rabbit, R-15, and Dantalian videos. Don't remember if they were all the same kind of setup as now, though.