I've been noticing this on and off for a while, but, since I have a work-around, I figured it was ok to ignore it.
As background: I buy quite a few disc titles every week; it's a pleasant obsession, and I do manage to watch almost all of them! I convert each disc to an unprotected ISO on NAS for backup and local playback purposes via Dune players around the house.
My workflow involves using someone else's unprotection software, then starting up to five instances of ImgBurn. Obviously, up to 5 Blu-ray drives are involved.
I set up each instance of ImgBurn to rip to ISO, and point each one at the correct NAS folder and filename, and then start READing on all the instances, one after the other.
If I click on the READ icon of each instance in quick succession -- less than a second between clicks -- then at least half the time one of the instances crashes, usually within seconds.
If, instead, I click the READ icon on one instance, wait until it is reading sectors, and then click the READ icon on the next instance, wait until it is reading sectors, and so on, then none of the ImgBurn instances crash.
If I had to guess, the initial phase of determining read speeds, drive capabilities, disc size, parsing the UDF (?) data might cause some kind of interference between the instances that doesn't happen during the reading of sector data.
I can provide further information if you tell me what to look for, if you think this is worth investigating.
Cheers,
--michael