When the thermostat in my fridge turns the fridge on, my coffee grinder (which is pretty much industrial strength and I presume on the same circuit) goes, “chunk”. It sounds like the motor is going a quarter turn then stopping abruptly.
Sounds as if there is some electrical spike being generated (expected) when the fridge starts and the coffee grinder, which presumably has some sort of electronic motor control, is being affected by said spike - which should not happen.
Probably the suppressor in the fridge motor has failed/is failing.
Not sure what the problem with the coffee machine might be.
I would say it’s more likely caused by the high draw of the frig motor starting rather than a spike. You would not expect the coffee grinder to be drawing anything while standing there, but if it has any display mechanism it may always be drawing a tiny bit of power. The frig high draw reduces power to the grinder for an instant. The poster could check this theory out in part by unplugging the grinder and plugging it back in. If he hears the same noise as the grinder resets itself, than obviously the power draw from the frig is the cause. Maybe he needs more dedicated circuits for the kitchen.