Once a week or so, this Schindler 3300 with TSD (low headroom) function, will fault with a error 0019

E_ELEVATOR_WATCHDOG_RESET
Indicates that a watchdog reset (initiated by hardware or
software watchdog) has been performed previously. The
elevator main control has just started up.
C1:A main controller software internal problem has occurred
A1:Verify if a main controller software update is available as
fix and update accordingly

There's also a STARTUP code with it

On arrival the system is on Inspection, with the two LREC and LREC-A leds on the main print blinking.
When I push the reset/inspection button, it beeps but does not reset the inspection.

Anyone have any info on this issue? Main card faulty?
It's a rel. 5 or 6, haven't confirmed the version yet.