It appears that its not the tablets, its the smelteries. After putting the controllers back on them, the problem popped back up the next time the chunk loaded. Went in and broke all the controllers again, problem went away after about a minute.
The tablet was misleading because it was attached to a smeltery. I'm 100% done with smelteries until the bugs are fixed with them. Iron hasn't worked, the drains randomly stop pouring into basins, nuggets stop melting causing me to have to remove/readd them manually, and now this lag issue. I'm just going to tear all of my smelteries down and leave'em down.