I have one project on my resume that I have trouble remembering some details of. It feels weird to drop it off (it was an internship at a sort of well known company), but it was a while ago. Is “can’t remember details” still a huge red flag from the employer’s point of view, even if the explanation is legitimate?

It’s not exactly the crown jewel of my resume anyway, so I guess I could cut it, it just adds to my backstory.

People understand that memories get foggy over time. Well, at least most people will.

As an interviewer I allow for a sliding scale of inability to drill in on details based on how much time elapsed. Also, you'll find that people are typically pretty consistent in what they retain. Like they'll remember the big picture, key challenges, and outcomes. but they may not remember a specific technique used or other day to day decisions.

For my own resume I do a similar adjustment. As things start to age out a bit I intentionally provide fewer specifics. Again, people understand what signals like this mean.