Sometimes operations have wrong collection names. Take a look.
First of all, there's a leading question mark instead of first letter (that should be 'p').
Apart from that, first entry looks ok.
Second entry is wrong. This query is one of several that are ran against pravdorub_production.answers collection. Also, it claims to be an 'update', but doesn't look like one (where's actual update part of the query?)
Third entry is also wrong. Answers' _id type is ObjectId, not Integer (vk_users has integer _id).

I am pretty positive that my code queries appropriate collections.

Also note that first and third queries are the same, only collection name is different.

{
"opid" : "moscow:1562954",
"active" : false,
"lockType" : "read",
"waitingForLock" : true,
"op" : "query",
"ns" : "?ravdorub_production.vk_users",
"query" :

{ "_id" : 13871986 }

,
"client" : "10.0.0.6:42150",
"desc" : "conn"
},
{
"opid" : "moscow:1562963",
"active" : false,
"lockType" : "write",
"waitingForLock" : true,
"op" : "update",
"ns" : "?ravdorub_production.vk_users",
"query" : {
"_id" : ObjectId("4d6ebda99b3b49619400014d"),
"uiq" :

{ "$in" : [ 96474834, "96474834" ] }

},
"client" : "10.0.0.6:42157",
"desc" : "conn"
},
{
"opid" : "moscow:1562955",
"active" : false,
"lockType" : "read",
"waitingForLock" : true,
"op" : "query",
"ns" : "?ravdorub_production.answers",
"query" :

{ "_id" : 13871986 }

,
"client" : "10.0.0.6:42174",
"desc" : "conn"
},