Photos.app states there are already imported photos on my phone, but I can't find them anywhere.

Sorry, it somehow doesn't allow me to update my original post:

When I connect my iPhone SE to my MacBook Pro (High Sierra 10.13.5), in order to import some photos, Photos.app states there are a 1000+ of already imported photo's in Photos.app. It even shows which photos, (almost) all photos from bursts. But I can't find them anywhere in Photos.app. Not by browsing to the corresponding time and date, nor do they show up in the Bursts album. Upon trying to import those photo's I get an error message that it will not import duplicate bursts.

How can I fix this?

Ah that explains. I started to edit my post, got a phone call, came back 30 minutes later, finished editing, hit 'save reply' and got an error message saying I didn't have permission to edit the post. Because it had been more than 15 minutes.

Thank you for your reply. It explains my problem to a certain extend. However, I've had this problem from before High Sierra was released (I was hoping an osX update would resolve the issue). The problem started when the bursts failed to import correctly in the first place. So it's not the case that I deleted the bursts which now gives me problems, they didn't import correctly at all.

There are some very nice pictures amongst the labelled 'duplicates' that I would very much like to transfer to my MacBook. Any thoughts of how I can accomplish that now?