Unbalanced data repartition between shard

Ops and Admin Sharding
6

Well I think I have a workaround for the mergeChunks problem.
I think this is somewhere related to a Bson de/serialization problem

I’ve mounted a sharded database with a simpler partition key : {action:1}
The action values are integers

if I execute a command like this one in a mongo shell or in Robo3T :

db.adminCommand( {
   mergeChunks: "test.cases",
   bounds: [ {actionId:191)},
             {actionId:250)} ]
} )

Then the command fails on a DuplicateKey error

Now if I execute a script like this one

db.getSiblingDB("config").chunks.find({ns : 'test.cases', min:{actionId:191}}).forEach(function(chunk) {chunk1=chunk;});
db.getSiblingDB("config").chunks.find({ns : 'test.cases', min:{actionId:250}}).forEach(function(chunk) {chunk2=chunk;});
db.adminCommand( { mergeChunks : 'softbridge.cases' , bounds:[chunk1.min,chunk2.min]});

Then the execution is OK.

I think there is at least a documentation bug here