This felt like it could be related to #33202 but my regex_replace tasks won't even parse successfully if I do not escape all backslashes in my regex. ansible 2.5.0 ...
$ansible-playbook a.yml -vvvv ansible-playbook 2.7.1 config file = None configured module search path = ['/Users/hryamzik/.ansible/plugins/modules', '/usr/share ...