Get_query auto-filling in some cases

I have some get_query in my maintenance visit purpose child table, the query is working fine, but I’m having a little problem there.
The query is:

frm.fields_dict.purposes.grid.get_field('scheduled_to').get_query = function () {
	return {
		filters: {
			'department': ['in', ['Diretoria', 'Assistência Técnica']]

The problem is that the field is auto-filled if the user who is logged in is part of this filter group. But I do not want the system to fill this field automatically, because that user can schedule to another user.

did you make the purpose child table as a customization by yourself ? and what version are you using if you created the purpose child table as a customization please give us a screen shot of it

No, I customized the existent purposes. Just added some fields on it.

you can create a custom script that clears the user field when you add a new row to the child table you can go to this page to know how to add a logic when new row added to a child table