Well, ADL should not miss incoming SMS messages - but it is now well-attested that it does!
Therefore, something is certainly wrong, and it may well be that the fault lies in adl_atUnSoSubscribe…
The fact that gsav has reported that other unsolicited notifications (RING, +CLIP, NO CARRIER) also stop working when the problem manifests would tend to point the finger rather strongly at adl_atUnSoSubscribe
See: forum.sierrawireless.com/viewtop … ibe#p23269