Neighbor's Base Station Interference? Is It Possible?

I will be honest; I am guessing this one. Recently, I arm my system, and it announces the warning that an entry sensor is open by name. The problem is that not only are all my entry sensors closed (in the app, and I check manually), but I do not have a sensor for a door it is announcing, and nothing is labeled as such in my list. This has happened three times in the past week and a half/two weeks. Additionally, in the same timeframe, I have found that I sometimes arm the system, and later, when I check via the app or Keypad, the system is randomly turned off – this has never happened before. When I arm the system, it will announce the standard message ("SimpliSafe on, Home"), and the Keypad will show it is in Home mode. Yet it disarms on its own.

The same happened when I left last week and armed the system to Away. When I reach my destination, I always check in on the alarm state (I have done this for years). However, the system was off this time, and I had to arm it to Away again via the app. And no, I did not make a mistake and forget to arm it. I set it via the Keypad and heard the beeps during my exit and locking of the door. My concern about a new, neighboring SimpliSafe system being the culprit came yesterday morning when I listened to what I thought was my alarm going off. I came downstairs, went over to my Base, and realized it was not emitting any sound. But when I went to the back of my residence, I could hear the siren (the same) coming from the window where a neighbor would be. If very close proximity of base stations can be the cause, it would also make sense that the sensor my base station is randomly announcing as open would possibly be linked to my neighbor's specific location door. The alarm went off each time my neighbor left and returned inside of their door (four times).

So, could my neighbor possibly install a SimpliSafe system that conflicts with mine? I do not wish to get too detailed regarding layouts, but that specific portion of their residence is attached to mine. If it is impossible, I have no idea why my Base is making an announcement for a sensor that does not exist and why its behavior is suddenly erratic after years of near-perfect function.

P.S. I have not added any new electronic devices to my home. Also, while some might suggest merely asking them, we do not have that type of neighborly relationship. Nothing is negative; they stay to themselves (which I see no problem with and understand). I have spoken to them only once since moving next door, so asking if they put in a new alarm would be odd.