George Michael did it with Freedom (1984 - with Wham! - and 1990 - as Freedom '90)
Madonna did it with Forbidden Love (1994 and 2005)
Kylie did it with Love At First Sight (1988 and 2002)

Have there been any other artists who've completely recorded different songs with the same title?

It's a boring example, but I think this has happened in a couple of instances with Glee Cast.

And I think T.I. has two songs called Whatever You Like.

I can think of two groups who have one song containing the title of the other:

U2 released Two Hearts Beat as One in 1983 then One in 1992.
The Saturdays released Up in 2008 then All Fired Up in 2011.

Puff Daddy's first two albums both contain a song called "Pain" that are completely different.