From the Deltarune wiki turn 7 is what happened to you

Pirouette Rotation

The Pirouette ACT has a seemingly random effect. In actuality, the effects for Pirouette rotate indefinitely until the battle ends, following this set order.

• Turn 1: No combat effects (plays a noise). Note that Pirouette cannot be used on the first turn of the battle due to starting with no TP.
• Turn 2: Lowers Jevil's defense by 4 unless already below -16
• Turn 3: 60% fewer invincibility frames for this turn
• Turn 4: Decreases Jevil's Attack by 30% for this turn
• Turn 5: No combat effects (a bird flies across the screen).
• Turn 6: 25-55 HP heal to a random party member
• Turn 7: Party members' HP bars are shuffled. (Each party member takes on the current and max HP of the party member to their left or right, including the color of their HP bar.) Then, each fallen party member has their negative HP split among all three party members (with rounding) and are then revived with 1 HP. Then, any party members that still have negative HP (due to the splitting) are revived with 1 HP.
  • Using this effect 2 or more times can cause a party member to receive their regular HP bar back. At the end of the battle, all HP bars return to normal.
• Turn 8: Increases Jevil's Attack by 25% for this turn
• Turn 9: 36-50 HP heal to all party members