Not to mention that linux users as a whole are not a significant part of the userbase
But, that is neither here nor there. I have a blanket policy these days of not spending time on issues that do not match at least one of the following criteria:
*) Are in calibre code
*) Have a clear chain of causality or are reproducible on my systems
*) Affect a significant fraction of calibre users
*) Require little effort
*) Can lead to data loss
This issue matches none of these criteria.
When you're one guy doing bug triage for software used by millions of people, that is pretty much the only way to keep your sanity. But fortunately, linux and calibre are open source, so if this issue bothers you, roll up your sleeves and trace the root cause of the issue and submit a patch with whichever project is the root cause of it.