I just purchased a 2 pack L-keychain-1 and one of the units is clearly defective.
I associated the good remote to my garage door opener with no problems.
Then I associated the defective one with the opener, the lights flashed as they were supposed to, but the remote would not open the door now matter how much I clicked. So I reassociated the opener again, the lights flashed again, this time I got the opener to open a couple of times with double clicks. but after a few goes even that stopped working. (all that time the other opener and original openers worked fine.
So I did the extreme, I blanked the whole system and started from scratch. I tried to associate the defective remote first. It took about ten clicks on the remote before it associated. All 4 other remotes (including the second remote of yours) associated immediately with one click.
I even changed modes and it would not associate at all.
This unit is clearly defective and I would like a replacement.