reverse spherification caviar left membrane residue in mouth when being eaten

[Aida14]

hi, my caviar left membrane that won't dissolve in mouth and stuck in teeth. i use frozen reverse spherification when making the caviar.. the membrane looking as follow. what could have cause the membrane to being unpleasant and being residue? do all frozen reverse spherification have this membrane residue . i use coconut milk and many other inggridient but still same result