Corgi Engine custom extension to the Jetpack ability that fixes three bugs with the built-in version. Tested with version 6.1. Usage: remove or disable the CharacterJetpack component and replace it with this

CharacterJetpackNoFlip.cs

using MoreMountains.Tools;
using UnityEngine;

namespace MoreMountains.CorgiEngine
{
	/// <summary>
	/// Add this component to a character and it'll be able to jetpack
	/// NOTE: This custom extended version doesn't perform a horizontal flip of the jetpack emission point
	///       because that flip already happens on the parent for some PlayableCharacter prefabs
	/// NOTE: It also prevents a bug in v6.1 that causes Jetpack refuel sounds and particles to play
	///       at the start of the game
	/// NOTE: It also prevents a bug where JetpackStop method was calling TurnJetpackElementsOff even while crouched
	/// NOTE: It also triggers a MMGameEvent when jetpack is refueled to allow more customization of that event
	/// Animator parameters : Jetpacking (bool)
	/// </summary>
	[AddComponentMenu("Corgi Engine/Character/Abilities/Character Jetpack (No Flip)")]
	public class CharacterJetpackNoFlip : CharacterJetpack
	{
		public bool dontFlipParticleSystem = true;

		// Fixes a bug with CharacterJetpack.cs in version 6.1 that has this initially set to true, 
		// which causes the TurnJetpackElementsOff() method to execute at the start of the game
		// which is bad if you have sounds or particles set for when jetpacking is stopped or refueled
		protected override void Initialization()
		{
			base.Initialization();

			_jetpacking = false;
		}

		// Fixes a bug with the position of the jetpack particles. No flip is necessary because the model flips itself.
		public override void Flip()
		{
			if (dontFlipParticleSystem)
			{
				if (_character == null)
				{
					Initialization();
				}
			}
			else
			{
				base.Flip();
			}
		}

		// Fixes a bug where JetpackStop was firing TurnJetpackElementsOff even if crouched upon release of jetpack button
		public override void JetpackStop()
		{
			if ((!AbilityPermitted) // if the ability is not permitted
				|| (_movement.CurrentState == CharacterStates.MovementStates.Gripping) // or if we're in the gripping state
				|| (_movement.CurrentState == CharacterStates.MovementStates.LedgeHanging) // or if we're in the ledge hanging state
				|| (_movement.CurrentState == CharacterStates.MovementStates.Crawling) // or if we're crawling
				|| (_movement.CurrentState == CharacterStates.MovementStates.Crouching) // or if we're crouching
				|| (_condition.CurrentState != CharacterStates.CharacterConditions.Normal)) // or if we're not in normal conditions
				return;

			TurnJetpackElementsOff();

			// we set our current state to the previous recorded one
			_movement.RestorePreviousState();
		}

		// Triggers a MMGameEvent when jetpack is refueled to allow more customization of that event
		protected override void PlayJetpackRefueledSfx()
		{
			base.PlayJetpackRefueledSfx();
			MMEventManager.TriggerEvent(new MMGameEvent("JetpackRefueled"));
		}

		[ContextMenu("Assign Particle System")]
		protected virtual void AssignParticleSystem()
		{
			ParticleEmitter = GetComponentInChildren<ParticleSystem>();
		}
	}
}