Yes, this one is on the user. I mean, it is clearly on the time of the FP, not like they hide it or anything.
And yes, all FP issued at the end of the time end up being less than 1 hour long. I mean, they could stop distribution 1 hour before close, so the final FP of the day is always 1 hour long but instead, they increase the numbers offered and shorten the window to fit in park hours. I guess the 2nd option is the better one. Fewer FP is never good, when you are looking for hard to get FP at least.
And there is a possible side benefit to those last hour FP, if the ride goes down for any reason, your FP turns in to an anytime FP for any ride at all 4 parks, short of the usual exclusions. I've benefited from that quite a few times.