Log Spam Warnings when adding a font in the Font Editor

Adding Font to a Font asset spams the Output Log with warnings

This is a Regression from 4.14.3

Warnings:

LogStreaming:Warning: Failed to read file '' error.
LogSlate:Warning: GetFontFace failed to load or process ''

1. Open any project
2. Add a new font (Add New > User Interface > Font)
3. Open the New Font Asset by double clicking it
4. Select Add Font

Result: The Output Log is filled with warnings

Expected Result: There is no warnings in the Output Log