Clicking/popping hamstring

I'm just coming to the end of Fundamentals and have really enjoyed it so far. I'm still very tight (can't easily touch toes yet) but am determined to put in the work to get more flexible.

I've come across something which I've found hard to find any information about. A long time ago (10-12 years) I pulled a hamstring in my right leg while doing karate. I had some massage/physiotherapy at the time and it seemed to heal ok. However, I've found that every day when I go into a straddle, that hamstring sort of "clicks". It only clicks once, and it doesn't hurt. After it has clicked, my leg can stretch more.

Is this anything to worry about? Will it go away over time if I keep stretching?

Any help would be much appreciated - I've searched online and haven't come up with an answer.

This is out of my scope but @Mark Collins and @Wesley Tan might have some advice for you.

Slight update on this - I've continued working on a straddle stretch daily and my leg doesn't pop anymore. Perhaps there was a bit of a knot there from my old injury...

The affected leg is still noticeably tighter than the other leg though. I'm taking things very gradually since I imagine it might need a bit of time to get used to the stretch.