Does anyone face this problem?
Is this not supported, the documentation is not clear
See, section : When null Means null
When choosing a suitable null_value, ensure the following:
It matches the field’s type. You can’t use a string null_value in a field of type date.
It is different from the normal values that the field may contain, to avoid confusing real values with null values.
Eventhough i am trying to convert the null string to "", it is not working, since event itself is not getting created so there is no use of applying filter