is this white ring of death :(

hi guys this is my first ever shrimp experience i just got two cherry shrimp a week ago and they were active and would even steal some fish flakes from the guppies this is also my first aquarium 17 gallon. recently one of them had been hidden for a whole day and today i found him with his buddy he seems active and brightly coloured however i noticed this ring. im not sure if this is natural colouration or a failed molt and im very worried