LSD was an "off the lot" option on U.S. 1995 Sportages but from the condition you describe it sounds like your Sportage doesn't have it. I would expect it to track fairly straight if it had LSD. But sounds like it doesn't, and my '98 without LSD would do the same thing as yours.

After about 1997 or so LSD wasn't available in the U.S./Canada as a factory installed option. You had to purchase the LSD unit and then have it installed. But it appears that in most of the rest of the world LSD is real common in Sportages.

1998 Sportage - Gone.
2004 Honda Civic Coupe.
2007 Suzuki Grand Vitara - She got it.