Quite a few people worry about this and, harp issues aside, it’s simply to give your XP something to do until the next level is released (originally, it just went to waste). It won’t stop you from automatically leveling up to level 27 on its release date.

This is how your XP bar looks during level 26. As you can see it’s the standard blue:

But, because there’s currently no level 27 (although fingers crossed on that changing this week), your blue XP bar is hidden for the time being and temporarily replaced with a pink XP bar, as you see here:

What happens then is that your XP accumulates on the pink bar until you get to a bonus level, where you have the chance to win up to 3 donuts:

Incidentally, this is the cause of the harp of death, so if you pass through it with no problems, it’s likely that the harp glitch won’t be a problem for you. Your XP will remain pink and reset to 0 every time you reach a bonus level right up until the time level 27 is released.

As soon as level 27 is available, you’ll automatically level up and your XP bar will turn blue again (with a bit of an XP head start).