Thanks for your response @Mike-Ubezzi-MSFT. I tried to respond to your comment but the site didn't seem to want to accept my input.
We're using the 3.6 API for MongoDB via the standard PHP driver. (Note we're on PHP and not Python :) )
$client = new MongoDB\Client(
$db = $client->selectDatabase("env-testing", ['typeMap' => ['root' => 'array', 'document' => 'array','array' => 'array']]);
$collectionName = "1_bindings";
$data = $db->$collectionName->findOne(["key" => "c1acce761bbf7d0810c5f5b71f3f20c2b75033eb"]);
This morning I ran a test, querying for a single item in the 1_bindings collection 10 times with 10 separate connections. All 10 were successful.
Then I deleted the 1_bindings collection, recreated it and added the same item. I ran the same test code 15 times and only got the document back 11/15 times. In the failure cases (2, 5, 11, 13), the server returned false as if the document did not exist with no other messages indicating an error.
Is there a way I can enable/access detailed logging in CosmosDB to try to further track the failed attempts?