Safari + Adobe PDF Embed API : ⌘F opens Find bar but cursor does not focus on search field

I’m facing a focus issue when viewing PDFs in Safari on macOS using the Adobe PDF Embed API 

Issue:
When a PDF is opened in lightbox mode in Safari using Adobe PDF Embed API 

• Pressing Command (⌘) + F opens the search/find bar

• However, the cursor does not focus on the search input

• Typing immediately after ⌘F does nothing

• I must manually click inside the search box or press Tab to start typing