As I'm sure many of you know, when DST changes occur in vBulletin—or other forum software, I'm sure, though I can only base my statements off vBulletin—times on the forum also incorrectly change: posts, last activities, etc. If you make a post the night before DST occurs at 10:30 PM, and then DST occurs the following morning at 2:00 AM—or, to be more technical, 1:59:59 AM since you don't see the clock actually change to 2:00 AM—it doesn't mean you suddenly made that post at 9:30 PM or 11:30 PM, depending on whether you're moving forward or backward, like the forum wants you to believe.
Using SEGA Forum, for example, it becomes even more complicated because their servers are located in London, and their DST changes occur at different times than in the US. So when they have their DST change in late March, for example, and the US has already had theirs, for whatever reason, the times become off and get an hour behind—or an hour ahead when falling back—between the hours of 6:00 PM and 1:00 AM (Pacific). After it resolves at 1:00 AM, previous times are still incorrect, however.
Here are relevant posts, all from the same thread:
And then a general overview since I stopped reporting the issue.
Anyway, for the TL;DR version, my question is simple: If you make a post at 10:30 PM in a vBulletin thread, but then DST occurs and you fall back an hour and vBulletin incorrectly changes the post's time to 9:30 PM, and then move to XenForo, where it does handle this correctly and doesn't change the times of content made before DST just because of DST, will the post still say 9:30 PM or will XenForo correct it to 10:30 PM, the actual time you posted it at?