I'm not sure what you mean by issues. Since my very first all grain brew, I've stirred every 15 minutes in the mash, and every time I add water for batch sparging. I'm usually very close to the predicted OG, and iodine tests are good. I've never tried any other methods, but this works for me.
I stir mainly to keep uniform temperatures. I mash in a rectangular cooler, the corner areas cool off much faster than the interior. If I didn't stir temps would be all over the place. If I need to add heat, I stir with a 1500 watt heat stick.
I'll stir the mash a couple of times to insure even temperature, especially when brewing in the cold. My mash tun is insulated some, but at sub freezing temps, it cools down on edges some. I run a 10 min recirculation at the end of mash. Running it longer cools mash down too much.
Someday may rig a HERMS or RIMS, but have been trying to keep it simple, and it seems to be working out so far.
I don't stir during sparge, as I try don't want to disturb the grain bed. One reason is to avoid a stuck mash, the other is not to stir up more cloudiness of wort that the recirculation cleared up. I tend to crush my grain on the fine side for good extraction efficiency, and post recirculation stirring gets more grain bits though the mash screen.
thanks guys. actually I am brewing 500 liters & 1500 liters by using Speidel Brand 3 in 1 braumeister Automatic system. But mostly I am brewing at Manual Method. That's why I have thick grain bed issue.
Anyway thanks for all of your reply. really appreciate!