Problem with FB input variable

PLCnext Technology & PLCnext Controls
1

Hi All,
I have an AXC F 2152 controller with HW 04 & FW 2021.6.0.
In general terms the problem is that an input variable of a function block called inside a 100ms task gets 0 value without the global variable passed to it at call going to 0.
In more detail:

  1. Modbus register is read through a read FB (Modbus TCP 11) every 200ms
  2. Modbus register is passed to a global variable inside an idle task.
  3. This global variable is passed as an input of a function block, called inside a 100ms task.
  4. Input variable gets 0 value at random points in time without the global variable getting 0

At first I thought maybe the function block got reset at random points in time, but that is not the case as the other input parameters of the function do not reset.
I have datalogger sessions, using idle task sample rate, capturing that incident.
Is there any insight about what can cause this behavior?
Thanks
Vaggelis

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