ISE 10 blowing trip on switch on

Had an odd one today, ISE 10 blows trip on swtich on but if trip re-set while still switched on will work fine and customer has been using it this way over the xmas period (leaving the mains switch on!.) Found NTC shorted to earth and have disable machine due to failing earth test until I get an NTC. Note to ISE, have emailed for one at your earliest convenience, Connect are out of stock. I know its your national holiday up there but….. customer waiting!