This type of error creeps in a lot when redrafting sentences. For example, maybe the submitter originally wrote "an actual debit card", then decided that saying "physical" instead would make the distinction clearer. It's very easy to just change the word and forget to check the words around it.

Edit: Or, as wrigby pointed out, they removed the word "(ugly)" from the techcrunch headline.

The actual headline is 'Venmo is offering users an (ugly) physical debit card,' so the '(ugly)' part complicates this. From a quick search, it seems like 'an' is correct here, because the '(ugly)' part isn't an independent clause... or something like that.

No, you're not crazy, "an ox", "a fox", "an apple", "an physical debit card".

All but the latter roll off the tongue. Must be the same in French with the liaison -- wonder what the equivalent butcherings are ;-)

I don't think a native speaker would ever make this mistake - it sounds incredibly awkward. It's not in the same class as many well-known and common spelling mistakes, like grocer's apostrophe, loosers, and others. This case the poster probably went back to remove the missing word because of the character limit on HN descriptions.