inquisitive1

Hi, I have a 2006 Subaru Impreza but over the last 5, 6 months i've discovered at random times I either can't use the remote to either lock or unlock my car. Like some days I come home from work yet I can't lock my car... yet another day I can. Or the next morning I can't unlock my car... or my favorite... I go out to run an errand in under 15 minutes yet when I get back I can lock my car. At first I thought it was just my car but the last three days i had a newer Forester as a loaner while my car was being fixed and discovered that the Forester also had a similar issue but more towards unlocking the car. I just found out today that my Mom's 2006 Tribeca also has the same issue when she visits. At home is the only place this occurs so I'm thinking some new person in the neighborhood has something that's used at random times that interferes with Subaru's. My sister has a CRV and she never has this problem. Has anyone else run into this issue cuz its starting to drive me up the wall! If so any idea what causes it or if it can ever be fixed? I've taken my car in once to the dealership and they found nothing wrong just said 'jump up and down' or 'unlock or lock in a different position' (yeah like any of those suggestions ever worked) Thank you