Steps to reproduce:

1. Navigate to Special:WhatLinksHere of a page with more than two backlinks. https://test2.wikipedia.org/wiki/Special:WhatLinksHere/Main_Page
   1. If the number of backlinks is less than double the limit (default 50), set limit to a lower number: https://test2.wikipedia.org/w/index.php?title=Special:WhatLinksHere/Main_Page&limit=1
2. Click on "next" at least twice.
3. Click on "previous" once.

Actual results:

• After clicking "next" once, the URL query ends contains &from=290&back=0
• After clicking "next" a second time, the URL query contains &from=789&back=290
• After clicking "previous" once, the URL query contains &from=290&back=290

Expected results:

• The URL query of "previous" should contain &from=290&back=0 instead of &from=290&back=290.

Browsers used:

• Chrome: 71.0.3578.98 (Official Build) (64-bit)
• Microsoft Edge: 42.17134.1.0
• Firefox: 64.0 (64-bit)