I've noticed this too around here. Titles will be changed and their meaning altered, effectively putting words in the original author's mouth. Seems kinda unethical to me, but it happens all the time.
HN automatically edits out some patterns from titles. If it happens to you and you want to put it back, you can just edit the title again after submission and it will stick.
Check the guidelines, it encourages neutering headlines in multiple ways; believe the idea is people can form their own judgement on whether it's good or bad.