INPUT problem with DateTime

I set up an action “COMPLETA ATTIVITA” that takes advantage of the new INPUT function. Unfortunately it seems that formulas using DateTime fields don’t work correctly.

For example in this simulation I should set:
[INIZIO] = current time - 1 hour
[FINE] = current time

Instead, it seems to keep the values ​​of the fields already filled in previously. Can someone help me? Is this a known behavior or am I doing something wrong?

this is the configuration:

And this is the behavior: INIZIO DateTime field is not changed (always 10/06)

Does anyone have any updates on this behavior? @Arthur_Rallu