It does look to me like this software has hidden bugs in it which can take years to become known because it all depends on how the software is used.
Despite my promise to myself to ignore you, do you really think MB, or -any- software would be "deliberately confusing and frustrating"? Seriously???
It's been proven by your previous posts that you haven't even started to climb the learning curve that's required to use MB. MB does NOT delete things (artwork, tags, files) unless you have enabled an option to do so. As hiccup stated, do some research, and demonstrate how MB is responsible for your many issues and that they're not due to your lack of understanding what you're doing.
There are many tens of thousands of folks using MB. New users show up all the time. For the most part they search the Wiki and the forum first and then experiment. -Then- they ask questions. Without accusing MB as being the problem. And those who do think MB is the problem are usually smart enough to move to some different software.
Have you actually searched the forum for disappearing artwork? There are a few threads from way back and where it was proven to be an issue with MB, a patch update was released and the issue was resolved.
So again, it's on you to show the developer that your artwork is disappearing due to a fault with MB.