First row added in a multiple value field is blank

Problem/Motivation

During manual testing for #3388482: How to reset value I noticed that in a multiple value field, whenever I clicked to add another item, the first row produced was blank. Looking at the screen capture in that issue, I can see that others have encountered the same issue.

Steps to reproduce

Create a bundle with a color_field that accepts multiple values. Create an entity of that bundle, and then click to add another item, and observe that the resulting row is blank. Click again an observe that subsequent rows function as expected.

Proposed resolution

Update the multiple rows handling.