This happens to me most dives, I can go down as fast and as deep as I want, then the first ascent (even up ~10ft to swim over some coral) it happens. Severity is not dependent on debth. After that I can go up and down without problem.
Probably not Narcosis - it has happened at 20' and at 80'
Visibility is usually 60'-80' and the water is 85F-87F (I have complained that the water was cold, when it was 83F)
Phew, glad I'm not the only one - I get exactly the same - the first time I make a small ascent, a few seconds of spinning, then fine.
Still, I get medicals every year and there's never a problem there.