Wow this is very interesting stuff and could actually be the issue. I have several case logic binder that can store more than 250 disc each. They are heavy. I have them stacked horizontally 2 binders high. Horizontally because I didn't want the sheets of disks tearing away from the binding if I had the binders sitting vertically.
It does seem that the BD-Rs are more sensitive to this then the DVR-Rs.
Below RitekG03 burned 11/10. Stored under same conditions using same burner.
Below TYGO2 burned 4/09. Stored under same conditions using same burner.
I believe this is probably the issue. Stacking them. I have a lot of BD-R and DVD-R so jewel case probably not a good a solution. I'll switch to having the binders to having the binders to vertical.