Performance degradation with Azure Functions

Question

I'm using azure functions and service bus and i'm facing some problems with messages consumption on queues with the passing time. Sometimes takes me less then one second to consume a message, others take almost 2 minutes and they start getting degradated more and more. i already tried alawys on, warming up the functions, none of my tries helped me to improve this functions performance and i have some queues that depends on a fast processing.

The only thing that helps me is restarting the function, for example, the function is taking 10 minutes to proccess 5 messages, when i restart the function, this will take less then one minute to proccess the same amount of messages, and i will join a loop that in 2/3 days the proccess will get slow again, until i restart the function once again.

Here's an example from the function response time before and after being restarted.

It starts with a fast response time and gets degrated with the time being, when i restart the function, the respose time drop radically.

I would like to know if someone faced this kind of problem and i'm looking for some answers.