The "Propane Alarm" is most likely an LPG (propane) and CO combination alarm like the one in my 2018 model TT.
Mine started acting up about a year or so after I brought it home new. Apparently the thing was telling me it had "aged out" and would sound off at the most inappropriate times (like 2:30-3:00AM).
I cured the problem by replacing the entire unit with a separate LPG alarm and then replaced the cheap (as in lousy) Smoke Detector with a combination Smoke Detector/CO detector alarm from Kidde.
Has worked flawlessly since.
LPG is heavier than air so the detector logically belongs near the floor. CO, on the other hand, is slightly lighter than air so it's not logical to place a CO detector at floor level.
Another benefit, when one or the other section of the combination detector fails you have to replace both at a significant expense. When separated as I've done, failure (or aging out) will only require the replacement of ONE at significantly less cost (and you get a better smoke detector