Hopper Lock doesn't work

what I mean by hopper lock is that when you powered a hopper with redstone signal, that hopper will not receive any item. I tried making item filter, that's when I found this bug. The Item still go through the hopper even when I powered it.
I hope I didn't miss bug report that is similar to this because I tried find a bug report about hopper lock but I didn't find anything

thank you