Sortable Property Display Name cleared on pagination

[sdtonkin1]

Version used
3.14.2

Describe the bug
When adding a Sort By Property in the search results web part, the display name of the property is initially shown, but removed when navigating to a secondary page through pagination for that result.

To Reproduce
Steps to reproduce the behavior:

1. Add multiple Sortable Properties to a result web part.
2. Sort by one of those properties in the drop down.
3. Scroll to pagination and select a secondary result page (2-X).
4. On result reload, the Display Name of the Sortable Property is reset.

Expected behavior
The expected result would be to retain the current Sort By property, there does not seem to be a current bug with retaining sort order across new pages, just the display name is reset.

Screenshots
Page 1

Selected on Page 1

Result on Page 2

Desktop (please complete the following information):

• Tested across Chrome, Firefox, Safari