Remote systems which use a "rolling code" can fall out of
synchronization (the receiver expects a different code than the remote
is sending) for any of a number of reasons:
- You accidentally push the button on the remote while "out of range"
of the receiver. This can happen pretty easily if the remote is in
your pocket... sort of like "butt-dialing" a phone.
- There's another door opener of the same brand and type located
close to your home, and your receiver "hears" transmissions meant
for your neighbor's remote.
In both of these cases, when you try to access the door, the "rolling
code" part of the transmission it makes is in a different part of the
sequence than the receiver expects to hear.
The receiver will typically treat this as either a brute-force attempt
to open the door, or a "replay attack" (somebody recorded your
transmission and is playing it back).
The systems often have a "resynchronization" feature, in which
transmitting a long series of correct codes in the proper sequence
will "convince" the receiver that the remote is the right one and is
properly paired. The receiver then resets its sequence to match that
of the remote.
The "up to a dozen times" sounds reasonable for a resynchronization.
Check the manual for your door opener - if it has this sort of
rolling-code/resynchronization architecture the manual will probably
say so.
If that's your problem... you'll probably have to live with it... but
maybe keep the remote control in a place where its button isn't likely
to be pushed by accident.