Pretty common unfortunately. It's why a lot of people feel it's imperative to keep a cover/lid on your tank.
I had a H. chrysus that jumped 7 times (while I had the screen top off to feed or do maintenance), 3 times in one week. He still lives in a friends tank.
i walked by my tank (without a screen top at the time) to grab my keys from a table nearby and it apparently scared my female clown. i just heard a splash of water and looked around the tank and sure enough there she was. screen top put together and on the tank later that day!
she has since jumped two more times, but ended up in the overflow due to screen top
My mccoskers is crazy he always jumps and turns at the last second and splasher water at me while im sitting watching TV lol, and hes jumped twice while ive been feeding and he never sits still to let you pick him up easily its like he wants to die lol.
A top of any kinda is better than no top