I use a Samsung Galaxy S5 smartphone running Android 5.0 (does phone carrier, kernel version, or anything else help?). I had some bugs that persisted after the 1.2 automatic update, so when a friend told me 1.2.1 added a Halloween theme but my update was late, I backed-up my saves to the cloud and manually uninstalled and reinstalled. Not sure if it makes a diffrence, but it wouldn't reinstall untill I cleared more space on my device.

I've noteced there is frequently an omonous three-note tune on a piano that plays when he arrives and a chime about 15 seconds later when he leaves, but simetimes I realize I've been looking for him for closer to a minute without hearing his chime, spot him without hearing his tune, or hear his chime without the preceeding tune. That same friend has told me that he has only spotted him 3 times using an older tablet, but has never heard any of the new sound effects I've described! The volume of the Mysterious Stranger's sound effects even changes sometimes, I thought it could be a clue to how close to the center of view he is, but haven't experenced enough to confirm.

Having another incident while looking for him is rather frustrating, would the developers please disable the overlap like they did with a production room's Rush Mode??? Also, the moderators didn't update the pinned http://www.gamesas.com/topic/1530844-fallout-shelter-update/ for 1.2.0 and it would realy be nice to know the rules of his appearances... frequency, payout, etc. but they never seem to be that detailed like other companies do.