Sister!

So, my sister took a pregnancy test last night, but she said she forgot an checked it after a while, like 10-15 minutes later and it showed up glaringly positive.. every other test she has taken since then has been negative. I know false positives can happen, but I have never seen a “false” positive look at clear as this. Adding a photo of the first test she took and then one this morning that appears negative. Any thoughts?