I think this one counts.
So I recently got a new job with a new company, and joined the 401k plan. The way the 401k plan here works is that you can have up to 17% of your paycheck automatically deducted each month to be put towards the plan. On the site, it states that the maximum allowed per year is $17,500 (per IRS regulations). The employer match sucks, but I don't think is too relevant for this post (in case you're wondering, it's up to 5% each month, up to $1,750 annually).
Anyway, if you contribute 17% of your paycheck each month, you would need to make approx. $103,000 per year to automatically hit the $17,500 maximum. Since I make less than that, I can't reach the max through standard deductions alone. Nowhere on the 401k site could I find a way of allowing me to contribute the remaining amount (about $5k in my case).
So, I went to HR and asked them about this. After a bit of back and forth and me explaining what I understood the rules to be, their answer was: "17% is the max. or $17,500, whichever is lower."
Me: "So, if I make $100 a year, I can only contribute $17?"
HR: "Err...yes, it seems that way."
Me: "Weird...I'm guessing nobody has ever asked you this question before?" (company is 20+ years old).
HR: "Yeah, nobody's ever asked that before!"
Now granted, I might be the only person in the entire organization of 200+ people that makes less than $103,000 and thus be the only person that has had to think about this...but I highly doubt it.