I found a solution for above bug.
We can override following file in theme
lib/web/mage/validation.js
Theme path:
app/design/frontend/'Magento/luma'/web/mage/validation.js
There find the rule: 'validate-email': and then replace
function (v) {
return $.mage.isEmptyNoTrim(v) || /^([a-z0-9,!#$%&'*+/=?^_\{\|\}~-]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z0-9,!\#\$%&'\*\+\/=\?\^_
{|}~-]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)@([a-z0-9-]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(.([a-z0-9-]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])).(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]){2,})$/i.test(v); //eslint-disable-line max-len
},
To
function (v) {
return $.mage.isEmptyNoTrim(v) || /^([a-z0-9,!#$%&'*+/=?^_\{\|\}~-]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z0-9,!\#\$%&'\*\+\/=\?\^_
{|}~-]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)@([a-z0-9]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(.([a-z0-9-]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(!.)).(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]){2,})$/i.test(v); //eslint-disable-line max-len
},
There we have added (!.) "not .(dot)"
Thank you