I opened up the crate and got the following message.
The Crate Contains:
1 Abysmal Rift Trap(Artifact)

Now I am not complaining, but this seemed weird b/c I thought that was the rare drop from a lvl 6 base. Is it b/c I did somewhere around 60-75% of the damage to the base, or was it a glitch?

They are a rare drop from 5's as well. I daresay you could call it an extremely rare drop, but not a glitch.

So maybe somewhere around the 1% chance mark?

Guess we need to update the wiki then.

Got it from my second level 5 raid. Consider yourself lucky you got it from a level 5, Will.

*pokes Xzien* Not many here know my name

Way to keep bumping the thread then