... Temporary solution is to disable mod_security on the account/domain in question.
No, I just switched to OSWAP rules until fix that. No need to disable mod_security.
Disabled Comodo rule with ID 218500 until fix. OWASP causes other incompatibilities so this way we can continue to use Comodo and no need to disable mod_security.
Added..
SecRuleRemoveById 218500
..to /usr/local/apache/modsecurity-cwaf/custom_user.conf