Sydney responsive works with main domain but not 2 forwarded domains


Main site is , all is fine, domain purchased while setting up the Bluhost and Wordpress accounts. However, I have 2 more domains purchased through Google / pointing to the site that work fine on desktop but not on any mobiles or tablets.
They initially load showing desktop version, attempt to change to responsive then blow up so big you’re left looking at an extremely magnified/zoomed in version of the site, totally unusable.

Please see screenshot for a few details, link:

Any help greatly appreciated.

Looks I’ve fixed it myself, I’ll leave this up here for anyone with same problem.

Changed the forwarding from a ‘hidden redirect’, to a ‘301 redirect’.

Took some time to propagate but all working for now.