yes andy,
even as handy as those ezfill systems are they are not fullproof. They do require maintenance and those cap floats and level indicators do stick after a while.
I had one in a reach truck one time that the floats would not shut off the water completely and wound up spilling onto the floor from a couple of the cells, overfilling those cells, i had to replace the caps on those cells.
It pays to check them once in a while physically to make sure all is in good order with the caps, hoses etc.