I'm curious what sort of issues you have in mind. I was never very familiar with BeOS but from what I understood the issue with it was more that its responsiveness came from very heavy use of multi-threading, but that also made it very hard to write robust apps for it as, in effect, all app code had to be thread safe. App devs found that condition too hard to handle.

Can I assume that the quality issues were somewhat related to that? BeOS devs found it no easier to write thread safe code in C++ than app devs did?