I also learned it back in 2004 and it was one of the single most useful skills I have ever acquired. My shoes never come untied anymore. Coaching baseball, when a kid's shoe comes untied, I re-tie it for them with the Ian knot. Life changing skill.

The Ian knot is just as likely to come untied the knot formed by the regular method or the bunny ear method. Because all result in the same knot.

If you noticed a change after you switched knots, you might have been inadvertently creating granny knots:

https://www.fieggen.com/shoelace/grannyknot.htm