Incorrect mongo documents count

Hi

I can’t figure out why mongo returns incorrect count on simple find request

db.registrations.find({}, {_id: 1})
{ “_id” : “qMD8QY35rxaoZ8pYn” }
{ “_id” : “XmdjLTTkZkQRSfKnn” }
{ “_id” : “8yg8sn8yHY6uMGvxo” }
{ “_id” : “RFTQHMJCSFGzvqsfd” }
{ “_id” : “pqaEdAqJZZ9ENTaQq” }
{ “_id” : “vQZnxCv9WR5ug2sok” }
{ “_id” : “jq3HJFJ6pLgzPXmpu” }
{ “_id” : “r7HFatr8RZ2ED7sLH” }
{ “_id” : “QbzzTdTgJmmJ69TNr” }
{ “_id” : “9rXYZ2mZyyGiyr6nZ” }
{ “_id” : “agqxHBkKr5NLCogb6” }
{ “_id” : “K5oTxnG65ZHB3xL6J” }
{ “_id” : “Lhxcihbcow9zJi9en” }
{ “_id” : “m46xETJSSktq3ENY9” }
{ “_id” : “Cud9zSxfbDGAuxswP” }
{ “_id” : “AGLparCn5BZnSsJvk” }
{ “_id” : “9jBLTLybxXXQmyYBT” }
{ “_id” : “d5SYoFHuC92jDKi26” }
{ “_id” : “PYZXB9TFiiaME5ms3” }
{ “_id” : “YrdFzcfNsLFjw6BuJ” }
Type “it” for more
it
{ “_id” : “cSbYqGMgMnqmjJgWR” }
{ “_id” : “fZAwwTFdJNhxXfFwt” }
{ “_id” : “z2yRniZLNemPHACTX” }
{ “_id” : “JhpnSfBYSnS34BuJ6” }
{ “_id” : “wFsqWNTYsL8fvtMyp” }
{ “_id” : “2DHjzSdAqzTSRXeTk” }
db.registrations.find({}, {_id: 1}).count()
25

There are obviously 26 docs, but count() returns 25. What could cause this?

Thanks