Increasing cpu load

I have had homeassistant (hassbian keeping it updated to current release 0.75.3 presently) running on a raspberry 3b + for some months now. Each time i boot it the cpu load approximates 2%. After one week it has increased to 4-5% consequently. And it keeps increasing to a point where i can observe performance reduction in the user interface.
Only cure is rebooting, which does the trick everytime.
Is this a raspeberry phenomenon or is it a homeassistant phenomenon ?. Is something cached and not flushed or what happens ?

the commands top and iotop may help tell if there there is a runaway process. You will need to install iotop with apt-get.

I read a number of observations of this. My conclusion from reading was the embedded mqtt has something to do with it. Thus i decided to try mosquitto instead.
This actually solved the problem.
I just wanted to share this observation to people with same configuration and problem.
My installation was done from this (manual installation)

and the HA runs as daemon