Villagers with blank or invalid items in their trades cause their chunk to fail to save

No idea what is going on with this one.... I am using command blocks to summon villagers and then removing the command block. However, when I save and quit and relog the command block has reappeared (some times with command some times without.) and the villager is gone.

I assume that this is some sort of save crash bug that will be very hard to duplicate... however, I did not see another post for this so I figured I should say something. If it will help I can try to post screenshots, or I can create a debug log (If that is helpful). Please let me know if there is a way to force a save or if there is something wrong with my file. Every block placement I do is saved, but the summoned creatures are not.

Here is a sample of one of the many commands I am using.

/summon Villager ~ ~-2 ~ {Profession:5,PersistenceRequired: 1,CustomName:Cow Herd,CustomNameVisible:1,Attributes:[{Name:generic.movementSpeed,Base:0}],Offers:{Recipes:[ {buy:{id:0},sell:{id:323,Count:1,tag:{display:{Name:”Cow Herd”,Lore:[“You Heard of cows?”]}}}},{buy:{id:371,Count:3},sell:{id:335,Count:1, tag:{display:{Name:"Bessy’s Milk"}}}}]}}