Cosmos Array_Contains Behavior in Different Partitions - azure

Question

In a Cosmos db, I have the following query:
SELECT
value app
FROM
Appointments app
where
app.PartitionKey = 'PartitionKey1'
and array_contains(app.Document.participant,
{
"type": [
{
"coding": [
{
"system": "http://hl7.org/fhir/v3/ParticipationType",
"code": "LOC",
"display": "Location"
}
]
}
]
}, true)
This works properly returning expected results.
However, if I remove the "system" and "display" items under "coding", making it
"coding": [
{
"code": "LOC"
}
]
the query works for Partition1 but not for Partition2, even though documents are structured the same, similar to:
[
{
"Document": {
"participant": [
{
"type": [
{
"coding": [
{
"system": "http://hl7.org/fhir/v3/ParticipationType",
"code": "LOC",
"display": "Location"
}
]
}
],
"actor": {
"reference": "Lo1",
"display": "Location1"
},
"required": "required"
},
{
"type": [
{
"coding": [
{
"system": "http://hl7.org/fhir/v3/ParticipationType",
"code": "SBJ",
"display": "Patient"
}
]
}
],
"actor": {
"reference": "Pa1",
"display": "Patient1"
},
"required": "required"
},
{
"type": [
{
"coding": [
{
"system": "http://hl7.org/fhir/v3/ParticipationType",
"code": "PRF",
"display": "Provider"
}
]
}
],
"actor": {
"reference": "Pr1",
"display": "Provider1"
},
"required": "required"
}
]
},
"PartitionKey": "Partition1"
}
]
The mysterious part is why this would work with one partition key but not another. It's almost as if one partition respects the true parameter of array_contains but the other partition does not.
Is there a setting on a partition, or some other property, that changes the behavior of array_contains?