On any frappe doctype, if you enter value into any linked field, two exactly similar ajax calls to
frappe.desk.form.utils.validate_link is performed. I tested this on version-13-beta, I am not sure whether this issue prevails in version-12. I tried to find the root cause and it seems like multiple same calls are performed in #L184 and #L187 of base_control.js.
I am not sure whether I am getting something wrong here but this seems like an obvious performance issue. Especially in DocTypes like Quotation and Sales Invoice that performs a lot of link field validations.
Same Validation Calls being performed TWICE