This is very interesting to me as I certainly have the hip pop issue. I do sit all day, but I work my hip mobility every morning and either before my workout or before bed after a shower. The poping does not hurt, but is does concern me with regard to long term hip health. When you made the comment to keep on training, does that have to do with your side work not curing your hip popping? I have always done some weighted step ups and split squats, but I try to keep them limited due to the idea of bilaterial deficit and that single leg work will increase it.
It is still better to be able to squat and do oly lifts for a long term rather than having my hip replaced in the next 8 to 10 years.
A little background also may explain some of the issues in that I was a competitive cyclist for about 5 years (3 years of 20+ hard race seasons) which was brutal on my hips and pelvic tilt. I will have both hips pop on occasion. While riding my chiro always adjusted me for leg discrepancy with the left leg shorter. While lifting my right leg tends to show up shorter.