I am curious if it was ever turned off
By default, the discord server security settings are not on the highest level, which this is. So yes, it was turned off at the beginning.
I suspect it was always on and spam was never a real problem and it was just preemptively turned on from the start.
Wrong. It was turned on after an influx of spam and troll accounts to make it harder for such accounts to enter the server and cause unrest.
In the beginning it wasn't turned on, which is why several people currently being members of our Discord server actually have no verified phone number with Discord, because the setting doesn't work retroactively.
Have you guys finalized the changes to the servers for the merger or is it still in flux?
They're final and will be posted at some point during the day today.