RTC task scheduler is stopped if another task locks interrupts longer then 2ms

Marshaller locks interrupts on netX50 for about 1,2ms. If such lock happens directly before the interrupt of the RTC task scheduler, so it delays ISR for about 2ms and causes skipping of the next comparing time for the next interrupt.
This will bring the stack into a state that cyclic communication is not possible. No AR can be established.