Trying to go to specific time marks on Youtube videos

If I’m watching a Youtube video and want to skip ahead, I click on the time bar at the point I estimate to be where I want to start watching. The video then jumps to that point, and begins to play from there, no problem.

But if I try to do it a second time, the video freezes, and as far as I can tell, will never play again for me, at least not for the next half hour or so.

Anyone know why this happens? (Does it happen for everyone?) Is it a measure to lower bandwidth? A glitch? Or what?

And is there a way around it?