In SharePoint Online I have created a new Site Collection with a custom master page, and the master page styles are displaying fine.
Now when I create a subsite they do not get the master page inherited.
Even though in the top level Site Collection I have checked the "Specify a master page to be used by this site and all sites that inherit from it" field.
I have to jump back into the top level Site Collection and click Reset all subsites to inherit, which then forces it to pick up the Master page, but this step shouldn't be required.
I had to turn on the 2 publishing features in the Site Collection to get the Master Page option available under Look and Feel:
- Turn on the SharePoint Server Publishing Infrastructure feature
- Turn on the SharePoint Server Publishing feature
Thanks for your help