P: Metadata panel jumps up and down as you enter fields

The fields in the Default, EXIF, IPTC Extension, Location, Quick Describe, and Video tagsets jump and down as you enter text in fields and tab to the next field.  When you hit tab, LR displays briefly shows an empty field at the top of the panel and then removes the field.  This is very distracting when you're trying to enter lots of data.

Here's a screen recording: https://dl.dropboxusercontent.com/u/21811200/metadata-entry-bug.2017.07.1.mov

This happens to me with new catalogs on CC 2015.10.1 / OS X 10.12.5, CC 2015.5 / OS X 10.12.5, and CC 2015.10.1 / Windows 10.  It doesn't happen with LR 5.7.1 / OS X 10.12.5.