Portenta H7: debug and no SysTick interrupts

When I try to debug my project:
Cube32IDE Portenta H7 FULL OPEN SOURCE project
with an external debugger (STLINK-V3SET) and I step through the code:
it does not progress: I hang in HAL_Delay().

It turns out as:
My SysTick is not running, the HAL_Delay() does not finish because the Ticks are not incremented.
I have used breakpoint on SysTick_Handler() (the INT triggered by/for SysTick) - it never comes.

Does anybody has a clue why the SysTick is not running, not triggering any INT (in debug session)?
Strange is: it seems to run on "non-debug" mode (no debugger involved).

As I understand:

SysTick is always running, just the system clock frequency selection/setting changes the period (set the right prescaler and also INT prio for SysTick)
The main interrupts, NMI_Handler up to SysTickHandler (as vector -1) - do not need and do not have an Enable function (enabled all the time).

But why is the HAL_Delay(), the SysTick not progressing?
What could disable this system interrupt?