Bosch RFKF-FBS remotes losing transmit distance ?

[joelau007]

I have this weird issue with Bosch RFKF-FBS remotes.
I have bought 3 units about a year ago.
On day 1 they were all tested, all 3 works fine when I'm standing on the driveway.
Now about 10 months later, 2 of the remotes seems to be losing transmit distance. I have to move closer before they will work.
Where else the 3rd remote still works fine while standing on the driveway. So I also can't fault the B810 receiver.
Of course the first thing I changed is the coin battery to eliminate that possibility.

Now I'm out of ideas. I have never seen such weird issue with remotes.

Any one with some other insights ? Have I missed something ?

[secure]

Maybe the remotes have been dropped a few times?

[joelau007]

I'm 100% certain they have not been dropped.

However, I just remember a difference. These 2 weird ones have higher temperature exposure, left in car parked outside shopping centre during summer, etc...
Still I see it as unlikely the Melbourne summer/winter weather would have pushed these simple devices beyond their specs.