I trimmed this down into the following to repro:
{
"L1": {
"L2": {
"L3": [
{"V2": {"K1": 0},
"K1": 0},
{"V5": ["A1", "A2"],
"V11": 1}
]
}
}
}
I filed a Jira ticket to track this and investigate it more.
https://jira.mongodb.org/browse/KAFKA-175