This may sound obvious but I just want to double check.

In First Edition, Stunned Pilot mentioned other ship and obstacles, but in Second Edition it only mentions obstacles. Does this no longer trigger when bumping another ship?

Correct. You must unlearn what you have learned

Okay, thanks. I just wanted to make sure it wasn't a case where the card's wording changed, but the effect didn't because of some other technicality, like other ships now being considered under the umbrella of obstacles. I could only find references to Asteroids and Debris Clouds being considered obstacles, but I wanted to double check.