Chrome Version: 66.0.3359.139
Windows server 2008r2

Steps To Reproduce:
(1) Add ADM template;
(2) Configure the RestrictSigninToPattern policy to allow two or more domains;
(3) Log in in the Chrome Browser

Expected Result: You cannot log in unless you use an account that is allowed.

Actual Result: You’re unable to log in with either specified domain accounts.  If only one domain is specified in the policy, then it works as expected.

When configured for ChromeOS via Admin Console, the policy works just fine with multiple domains.

How frequently does this problem reproduce? 

Always.

What is the impact to the user, and is there a workaround?
n/a

Logs (PII protected)
https://drive.google.com/open?id=14oAkslfgMLDTZRS8WuZSIhxmgnpf2nzV  - in this folder, you can find screenshots of the configurations for both 1 domain and 2 domains, along with a debug log.