Just to bring some closer to my post, this time I added 20 quarts of 185 degree water to my cooler/mash tun. Left it for 10 minutes and it was down to 171. Added my grain (note to self - stir while adding next time…Holy grain balls!).
Had to add 2 quarts of cold water to bring it down to 156. Also elevated the cooler off the floor.
After 1 hour, the mash was reading 154 so it only went down 2 degrees at most. Clearly my problem was my procedure. Thanks everyone for the suggestions.
Glad to hear you figured it out. Thanks for following up.
And yeah, pretty important to stir while adding grain to water 