Hi
we have replica set consisting of only mongo server 2.6 (we have upgraded a week ago) . we are running on windows server 2008 on virtual machine.

Recently we have noticed rather annoying issue: we have a collection called items_full which has a unique index on field sku. when we run following update query:
db.items_full.update({},{$set:{'ProductInfo.ProductCA.isUpdated':false}},

)

it crashes with error:
E11000 duplicate key error index: inventory.items_full.$sku_1 dup key: { : "DSSWI#Luc_W_Lp-12550-Gy-014-Gy" }

when i look for the above sku i get only 1 result.

Any ideas?