Wellnesscafe If the machine has leaks, e.g. steam constantly coming out, it is not surprising that the heater is permanently on as the machine operates with a pressure stat (here I am guessing as you mentioned a display, does it have a PID to control the temperature?) and as a result it never reaches the pressure (or temperature?) the pressurestat (PID?) expects whence the heater is permanently on. For the steam wand as @DavecUK has mentioned, it is likely that the inners need replacement. What machine is it, Aurelia or Apia?
You might need to tighten up the compressions as it is not normal the cups to be warmed up “by the steam”.
Given you rebuilt it up last year this should not be a big deal for you.