BuildCraft version:
7.99.13

Forge version:
forge-1.12.2-14.23.1.2566-universal

Link to crash report or log:
Singleplayer or multiplayer:
Additional information:
I haven't tested with all gates, but with the basic gate, once you place and configure it, you must open it again for redstone signals to activate as configured.

I'm having trouble reproducing - is your setup similar to this:

(Both of the gates are setup with Redstone -> wire or wire -> redstone).

EDIT: Note that I'm effectively using 7.99.14-pre2, although it didn't change anything todo with gates so theoretically it wouldn't make a difference)

I cannot reliably reproduce this. I will reopen as necessary. Sorry about that!