Azure Function App. moving messages to posion queue with no errors, warnings or exceptions

Question

We have an Linux based queue triggered Python Azure Function App. running on consumption plan. We have a process on another server to ingest about 4 to 5 queue message per second which can go up to a couple of thousand messages put in the queues in a span of 15 minutes. The Azure function app processes the queue messages and outputs the data to blob storage as expected by auto scaling and processing messages in parallel. 95% of the messages are successfully processed and then it stops invoking the messages and directly moves them to poison. Invariably, this happens while processing the last few batches of messages. I checked the invocation logs and also end to end transactions and it looks like there was no invocation after '2021-10-06 17:49:38.123' (UTC) and messages were being moved to poison queue for five minutes after the last successful invocation. I couldn't find any exception recorded in transaction/failure logs (EST). It looks like the function app instances shuts down refusing to process the last few messages. I looked up on the internet and found an issue related to what I am experiencing. I am unsure if this is a known issue or if there's something wrong with my host.json file. Attaching the necessary screenshots. Thanks in advance.

https://github.com/Azure/azure-functions-host/issues/6894

host.json

{
"version": "2.0",
"logging": {
"applicationInsights": {
"samplingSettings": {
"isEnabled": true,
"excludedTypes": "Request"
}
}
},
"extensionBundle": {
"id": "Microsoft.Azure.Functions.ExtensionBundle",
"version": "[2.*, 3.0.0)"
},
"extensions": {
"queues": {
"maxPollingInterval": "00:00:01",
"maxDequeueCount": 1,
"newBatchThreshold": 8,
"batchSize": 4
},
"retry": {
"strategy": "fixedDelay",
"maxRetryCount": 1,
"delayInterval": "00:00:01"
}
}

}