Mid-Operator supplies a faulty value (elimination)

Which products are affected?
EVS93xx-EI (Servo PLC Version 6.2 DSMC control board)
EVS93xx-ET (Servo PLC Version 6.2 DSMC control board)
EPL-10200-EI (Drive PLC Version 6.2)

What happens?
If the position '0' is selected as start character when using the MID-Operator, the operator returns the partial string starting with position '1'. However, operating correctly, the operator must not return any characters when selecting '0' as start position.
In general: The 'MID' operator provides a partial string from the string. The user himself selects the string, the number of characters to be supplied by the operator from the string and the start character from which the partial string starts.
For example in ST:
Var1:= MID ('LenzeAutomation',4,6)  (*Var1= 'Auto'*)

When does the problem occur?
When using the MID operator with a '0' start position for a partial string.

Possible diagnostics?
None.

Short-term measures/recommendations?
It must be ensured in the program that the value '0' cannot be selected as start position for supplying the partial string.

Evaluation:
The error only occurs when using 'String' data types which are used quite rarely in applications. The use of the 'String' data type does not affect the drive performance.