Can Doctrine constantly send requests to add an index to MongoDB?

Question

Doctrine ORM

The following lines are constantly found in the Mongo logs:

2015-01-26T11:45:32.617+0300 [conn18401] command common.$cmd command: createIndexes { createIndexes: "searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name : "uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:33 reslen:95 595ms
2015-01-26T11:45:32.617+0300 [conn18413] command common.$cmd command: createIndexes { createIndexes: " searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name: "uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:30 reslen:95 369ms
2015- 01-26T11:45:32.617+0300 [conn18405] command common.$cmd command: createIndexes { createIndexes: "searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name: " uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:31 reslen:95 183ms
2015-01-26T11:45:32.617+0300 [conn18373] command common.$cmd command: createIndexes { createIndexes: "searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name : "uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:26 reslen:95 150ms
2015-01-26T11:45:32.617+0300 [conn18363] command common.$cmd command: createIndexes { createIndexes: " searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name: "uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:31 reslen:95 232ms
2015- 01-26T11:45:32.617+0300 [conn18370] command common.$cmd command: createIndexes { createIndexes: "searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name: " uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:39 reslen:95 443ms
2015-01-26T11:45:32.617+0300 [conn18221] command common.$cmd command: createIndexes { createIndexes: "searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name : "uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:20 reslen:95 204ms
2015-01-26T11:45:32.618+0300 [conn18013] command common.$cmd command: createIndexes { createIndexes: " searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name: "uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:44 reslen:95 133ms
2015- 01-26T11:45:32.617+0300 [conn18399] command common.$cmd command: createIndexes { createIndexes: "searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name: " uuid_1" } ] } keyUpdates:0 numYields:0 locks(micros) r:45 reslen:95 687ms
2015-01-26T11:45:33.056+0300 [conn18400] insert common.searchResultForBasket ninserted:1569 keyUpdates:0 numYields:0 locks(micros) w:203102 184ms
2015-01-26T11:45:33.056+0300 [conn17853] command common.$cmd command: createIndexes { createIndexes: "searchResultForBasket", indexes: [ { key: { uuid: 1 }, unique: true, sparse: false, name: "uuid_1" } ] } keyUpdates:0 numYields:0 locks( micros) r:43 reslen:95 135ms

Those. for some reason, batches of requests to create collection indexes regularly come when it is never deleted and exists for a long time.
We work with this collection through doctrine.
Is this a feature of the doctrine itself? Or what could it be?