It’s actually pretty standard that when people take the test multiple times they get different results. It’s one of the reasons the test is considered meaningless, any psych test that can give different results on different days is at best a parlor game.
If someone gets different results, that can only mean they changed their answers. You can’t blame a test which asks about preferences for fickleness; you can only note that such fickleness decreases the accuracy (which is an entirely different measure than validity).
People like it because it is simple to "interpret," easy to take, and like horoscopes, has a positive interpretation for every outcome. Important when you have 20 million dollars in earnings at stake.