Specific variable "disappears" in 1.5.4 ?

In my main playbooks I define a global variable named “dns_type”, used in multiple roles. It’s simply defined like this:

vars:
dns_type: “CNAME”

This worked fine up to 1.5.3.

In 1.5.4, this variable turns up empty when I try to use it in a role. If I rename it to “dnstype” or “dns_foo”, it works fine. Seems like an oddly specific issue, and I haven’t found anything in Ansible that uses this particular name.

I’m not quite able to reproduce that on 1.5.4, could you share a small playbook/role that reproduces the issue for you?