I did observe when I pressed All On or All Off from the Admin Console for the system in the garage it turned on and off a nearby 2476D, which was never linked to this PLM. I tried adding then removing the 2476D, but it still is controlled by these All On and All Off buttons. Is this normal?
The PLM was new and I restored it before adding any devices (to "clean" it). The ISY-26 was previously used with this 2476D and other devices, but I did a Factory Reset before starting.
There shouldn't be any traffic from the garage - nobody's in there. Any programs and scenes are only for those devices connected to the test strip in the garage.
If your repeaters (any Insteon device) are distant this could create a problem (or at least use a Insteon HOP).