With other Siemens PLCs I have had the problem that under/over range check generate an alarm if the signal is 3.99mA. The 0.01mA may not be because that there is a problem but just because the attached sensor can function a bit below its nominal range.
I ended up making my own check that generate an alarm if the signal goes below 3mA.
Dont know about S7-1200, but I would guess it works in the same way.