Setting pager.add=true breaks add --patch

Given:

1) git version 2.10.0.GIT

2) The following configuration:
=======================
[core]
   pager = less -FRX --tabs=4

[pager]
   add = true
=======================

3) A patch hunk longer than a screen

THEN:

less will be invoked as expected.

However, upon exiting less, I am dropped back to the shell, whereas I 
would expect to see:
Stage this hunk [y,n,q,a,d,/,j,J,g,e,?]?

-- 
Tom Hale