The issues like #339182: node caching issues and #417668: Module sends old path to SWFObject API are cache related. Clicking on Flush Cache in the admin menu, or devel, doesn't flush flv related caching, either.

When you expect caches to clear, and they don't, admins end up frustrated and confused about why they aren't seeing the behavior they expect to happen.
Flush all should flush all caches, right?

The problem: flvmediaplayer doesn't implement hook_flush_caches.

Add this to the module and bingo, all is better.

function flvmediaplayer_flush_caches() {
  return array('cache_flvmediaplayer');
}