Materials I know that are chemically resistant to Sodium Hypochlorite (NaCIO) are PTFE and ECTFE. They are expensive but relativly easy to apply. It appears to be a liner failure.
I don't think your problem is with the teflon coating on the screws. If the stainless steel screw had been fitted to a steel substrate, it is the stainless steel that is causing the problem, not the teflon. Teflon does not have a spring effect. With the dia of the screw only being 1mm the...
