Could you outline (in pseudo code) a skeleton that captures your open/close cycle and read pattern(s), e.g., iterations? Without a reliable way for us to reproduce the behavior you are seeing, there’s not much we can do.
(Alternatively, with a support agreement + NDA in place, we’d be happy to look at your code.)
There had indeed been a support contract in the past, initiated by a former colleague of mine.
The read error could not be fixed because it occurred so randomly. In the meantime we could at least get the error message mentioned.
I can send you something, maybe you will discover the problem at first sight.
If we see a realistic chance to solve the problem, we can consider a support contract again.