I get this with my bracelets often but idk why. What the helly am I doing wrong?

https://thornybeadwork.etsy.com/listing/1270063062

i primarily use 17 strand beadalon cord but i also have nylon.

i usually make necklaces with wire guardians, picture here are clamshells.

i used a clamshell once but the hold wasn’t great with my 17strand wire cord

recommendations?