This isn't really a bug. In S2K combat, time is calculated based on the active players in the fight. The more power, the more time is added on until it eventually decides to go infinite. The moment it drops down back to a reasonable number, it will reset and start a countdown to end the fight. This is just how S2K systems work.
If you are stuck in a S2K fight, we recommend contacting staff in order to end it.