I have done a conflict test and have found out that it is a conflict between Ultimate Member and bbPress plugins.
When bbPress plugin is deactivated, the menu structure becomes how the way it should be for the ‘Standard’ user role. When bbPress plugin is activated, the menu structure changes to look like the ‘Premium’ user role’s – this ONLY happens when the ‘Standard’ user role is in the forum page. The forum page on my website is called ‘Enter the Community’. The image of this conflict is here.