Map will not remove from Etrex 20

New to the forums folks, just looking for a helping hand. I apologize if I'm missing something blatantly obvious here, but this is my first real GPS (Edit: Although I consider myself fairly tech-savvy. Have used Rhinos, PLGRs, and DAGR's in the past) and I've been googling this for hours now and can't find anything on it.

I picked up an Etrex 20 the other day for an upcoming trip and added some maps just to see the functionality of the unit. I didn't have a mini SD for it, so I just added 3 pretty random maps to the storage on the unit itself using mapinstaller/manager and basecamp. When I tried to remove the maps afterwards (per pg. 43 of the owners manual) I was able to remove each of the .gmapi files that I had added, but when I power on the unit and go to Setup > Maps > One of the maps still shows up as an option to enable/disable. The other two are gone (as they should be).

In addition to searching through each folder on the device itself, I did a search on my eTrex for the filename of the map (including hidden files) and it's not there. As far as I can tell, it's not on my garmin but it keeps showing up anyway. I can also access the map just fine, so it's not just the name of the map that got left behind.

Any idea how I can remove this file (or where it's being kept?) Did it physically add itself to the default map or something? Barring other options, how to I clear everything out and load up just the original default maps again? Tried a master reset, but that apparently only resets the default unit settings, not maps that were added etc.

Any help would be greatly appreciated. Thank you in advance