If a mongoimport statement is ran (importing 1000s of records), in the middle of a map reduce query the following error occurs:

uncaught exception: map reduce failed:{
"cause" :

{ "assertion" : "[test.example] shard version not ok in Client::Context: your version is too old ns: test.example global: 148|0 client: 147|1", "assertionCode" : 13388, "errmsg" : "db assertion failure", "ok" : 0 }

,
"ok" : 0,
"errmsg" : "mongod mr failed:

{ assertion: \"[test.example] shard version not ok in Client::Context: your version ...\", assertionCode: 13388, errmsg: \"db assertion failure\", ok: 0.0 }

"
}