The operationsBlockedByRefresh counters are increased on mongos for every operation that use collection routing information even if the operation haven't been blocked by a catalog refresh.
In fact all operations that requires collection routing information end up calling CatalogCache::_getCollectionPlacementInfoAt . In this function we unconditionally set the operationBlockedBheindCatalogCacheRefres boolean to true and when the operation completes we execute CatalogCache::checkAndRecordOperationBlockedByRefresh that increase the metric counters.
This metric has been introduced by
SERVER-46396 as part of PM-1633. The future flag for this project have been disabled because we discovered was causing performance regression.
This goal of this ticket is to remove this wrong and misleading metric to avoid confusion.