There are a couple other threads about this. It seems to occur when the cache is full: Firefox does not do the usual removal and replacement of older pages with the new one (for some reason I haven't learned yet). Two workarounds have been noted: * Clear your Firefox cache. Of course, this is temporary because eventually it will fill up again. E.g., https://support.mozilla.org/questions/1021662#answer-633386 * Switch from an auto-sized cache to a fixed size cache. See: https://support.mozilla.org/questions/1018237#answer-635776 (that's "3-bar" menu button or Tools menu > Options > Advanced > Network mini-tab > check the box for Override automatic cache management)

You can try to avoid this by right clicking the new link and select '''Open In New Tab / Window.'''