Googling on this is kind of useless. This happens because of the lag when the HT is summoned. Therefore when you hit the crystal too fast, 2HTs Spawned instead of one. That's when the glitch happened and when you try to go to the right side, it DCs you. You can stop this glitch by
1. Hit the crystal slowly. ( 6 Times )
2. Forget about killing HTs and get your rebirths up.
3. Totally quit maple.
Your choice.