Two blocks on a project page are held behind an active membership, and everything inside them goes when they go. The page does not say a control was removed, so the missing buttons read as a fault rather than a boundary.
The media block, and everything attached to it
The project's images, videos and embeds are the gated part. Signed out, you get a Sign in to view this project card in their place. Signed in without an active membership, and with your free views for the month spent, you get Your free access has expired this month.
The engagement bar lives inside that block, so it is replaced along with it. That bar is where Follow Project, Copy Link, Report, and, for the team, Edit and Delete all live, as well as the Grid and Full-width view toggle. Lose the media and you lose all of them at once.
The Associated Disciplines card
The disciplines card in the right-hand column is checked separately. It appears only for a member with an active plan, so it can be missing on a page whose media you can see, and it is missing entirely when you are signed out.
The disciplines themselves are still doing their work while hidden. They are what fills the Similar Projects strip and the discipline competitions strip further down the page, so you can see their effects without being shown what they are.
What stays regardless
The title, description, cover image, project score, ratings section, comments, team, connected journals and publications, location, licence and published date are all on the page for everyone. So are the five round buttons in the right-hand column: Like, Save, Comment, Share and Report. Those are a separate control from the engagement bar, which is why Like and Share survive while Follow does not.
What to do
If you are signed out, sign in. A free account restores a monthly allowance of project views, and while that allowance lasts the whole page is open to you.
If you are signed in and the block still shows the upgrade message, your allowance for this month is spent rather than your account being restricted. See Why can't I view this project? Do I have to pay? for how the allowance works and how to check your own.