Plugin Error: Object reference not set to an instance of an object when setting target es entity reference

Hi,

I've a plugin step registered on the create message of a certain entity. If I try to set the input param 'Target' as entity reference to another entity, which I'm creating in my plugin, I'll always get an InvalidPluginException withe the message "Object reference not set to an instance of an object". For me, it seems like I cannot set Target as an entity reference when my plugin get triggered from a create message.

Is that right?

Thanks in advance!