Seems ok to me.
If it is normal, sound should keep average the same as time goes
If there a problem, it probably will get worst and worst.
So, give bike a good ride, have fun and hope everything will be fine
Mark the nut and axle relative position first.
Than remove nut with a impact gun
Change seal
Reinstall nut with impact gun untill marks realign again.
This way proper tigtening is garanted
Sherco had (or still have not sure) different levers from others with same model master cylinder.
The pivot point in sherco give more leverage than others. So the lever should be specific for sherco's