Hi agambhir_be20
How many allowed substeps are defined? Is this being run as a large deformation analysis? Have you double checked the CZM properties? You may want to run a simple two element (like two cubes meshed each with just one element) test to make sure the debonding is defined as you expected. A simple typo could result in the debonding being too strong...I've made that mistake plenty of times to know!
Mike