I've discovered that editing the tile and deselecting "Auto Update" has resolved the issue. If you'd like to try to replicate this strange bug, create a tile with a google maps bookmark showing a specific location and set it to create a thumbnail from the page, leaving auto-update activated, refreshing every 1 minute. 

Thank you for your reply.

The behavior I notice is that Firefox opens a new window in the background and it happens to be the exact page that is set for the first tile of the first of 3 tabs that I've created. Something is repeatedly opening this tile as a new window in the background and then usually closing it immediately or shortly after. It's very annoying because it steals focus so if I am typing, I am interrupted and I need to click on the text box in my current browser to continue to type. My anti-virus program says I'm in the clear, and it's quite the coincidence that the window opens to a bookmark that I have set as a tile, so I assume it is this plugin that is causing this strange behavior.

I have a lot of tiles set up so I would like to avoid an uninstall.