All your loads have electric motors - which take a very large inrush ie startup current. This can cause interference as you found. The amount depends upon when exactly in the mains cycle the relay contacts close - unpredictable. Hence it wouldn't cause your reset problem every time.The same applies to turning off, with the extra problem of suddenly open-circuitiing an inductor - the motor. This can give a large voltage spike.
Adding a series inductor - your ferrites - slows down both these pulses, and reduces interference. A good solution
The various 'snubber' suggestions would reduce interference ( and sparking at the contacts) when the relay contacts opened . May also be worth doing to extend the contact life.
regards
Allan