I'm new to making espresso at home. I got a Breville Infuser and Smart Grinder a few months ago. The first few months everything worked fine. Lately however when I pull a shot the pressure gauge has started fluctuating quite a bit. As far as I can tell my grind and tamp are the same. I recently ran the first cleaning cycle on the machine after the "clean me" light came on. The coffee that comes out still tastes fine.

Is this a sign of a problem with the machine? Or something else? Or nothing to worry about?