Inaccessible view despite views being joined in explore

[tomstapylton]

Hi, I have created a new dimension "dimension_one" in my view "view_one". This new dimension references fields from "view_one" and "view_two" and the two views are joined in "explore_one".

I am able to use the dimension: the query runs, I am able to create, view and filter visualisations using the dimension in Explores, Looks and Dashboards.

But, when I validate my LookML I receive the following:  

Inaccessible view "view_one" referenced in "dimension_one".

 "view_name" is not accessible in explore "explore_one". Check for missing joins in explore "explore_two".

"explore_two" does contain a join referencing "view_two", but it is not referenced anywhere in "explore_one". 

I hope this provides enough information - what can I do to make sure my LookML Validation passes?