Service Bus Queue trigger not firing sometimes

I have i service bus queue triggered function (V1). When i publish it to Azure it works just fine for some time. Then it starts skiping some messages - no execution logs and message goes into dead-letter queue with "Message could not be consumed after X delivery attempts" error.

I thought it may be a cold-start issue (new messages arive in ~20 minutes intervals), so i tried increasing Maximum Delivery Count to give it more time to start. But that did not help.

I'm using Consumption Plan and i have put ServiceBusConnectionString in Application Settings.

The only thing that works for me now, is refreshing Function App in portal...

Here are the details:
Location: North Europe
Invocation Log: 2019-03-18T07:03:45.648 [Info] Function started (Id=4cb549cb-6fb1-487a-95af-9cc9850e3ad1)