There is no issue when clicking the Webex meeting link directly in secure mail.
Only secure mail for Android has this issue.
Checking Secure mail logs, after clicking icon “Join Meeting ” in secure mail Calendar, secure web visited a wrong webex meeting link like below,
https://xxx.webex.com/xxx/j.php?MTID=m5ab194a65f30000bb1caa3c083fd2;<URL Encoded contact info>
The correct meeting link should be: