I would like to know when we stopped using Lenticular slip covers.

I added the Slip cover Scans for Lords of Salem 013132-606309  (Blu-ray) and I was approved them it was changed with a non Lenticular Cover.
I resubmitted and now a user Comments this
"Probably because of this rule: If a DVD is packaged in a keep case, within a slipcase of some kind, scan the Cover Images from the outer slipcase. If, however, the Slipcase is reflective, and the inner cover art is identical, use the Keep Case art to"

I believe the person is misinterpreting the rule and it doesn't apply to this.

If we go by your interpretation of the rule, we'll have a lot of Slip covers to change. If we are doing away with Lenticular cover scans

We're not. I watched the whole changing of the covers thing on that particular profile go down, and I honestly don't think it was intentional.

What I think happened was simply there were a bunch of different covers pending at the same time (along with other updates). Looking over the contribution history, 10 different updates were uploaded (some pulled) over the course of like, two/three days. One with covers got approved on the 9th. Yours, as well with covers, also got approved on the 9th (two different sets of cover scans approved on the same day) and then another user re-uploaded what they believed to be just the back cover (maybe they hadn't updated it, maybe they didn't realize they were submitting the front cover, maybe they did and they were just being a jerk, I don't know  ) and that one was pending while yours was being approved (yours was submitted on the 5th, approved on the 9th... the other submitted on the 7th, approved on the 11th) and I think simply because there were too many hands in the cookie jar so to speak, that one, which changed the front cover from your lenticular scans to non lenticular scans, got approved.

I don't think it was meant to remove the lenticular cover in anyway at all on purpose. It just so happened to go down that way.

As it stands, in my opinion, the no vote is a smidge off base. The current cover (the non lenticular one) is not the cover from the keep case. If it were, it would be smaller as slip covers are larger than the keep case covers. The current cover image (the non lenticular one) appears to me to be a pre-release cover (or maybe there's another cover that's not lenticular out there somewhere?). So you're not replacing a "better quality image" of an actual keep case cover with a lower quality image, you're replacing a pre-release cover (which would be incorrect) with a correct slip cover scan. The fact that it's lenticular has no bearing on it at all, as it's simply the correct cover.

I voted yes to the change and will keep my vote that way.