This has caught me out a few times, though I am now getting used to it. The forum uses two formats for dates, MMM 'YY for dates before Jan 1 (currently), and MMM DD for dates in this year. The problem is these look very similar, so similar I have a few times caught myself reading them wrong. One example is the first and last messages in this thread:
Or it's easy to see in the dates in this area of the forum, when topics are sorted in date order.
It might well be as I am British, so am not used to US date formats. But that probably applies to many forum users. An option to either use local date formats or to never abbreviate years would make dates much more readable.
It looks like Discourse (the software these forums run on) doesn't have the ability to use locale-sensitive formats here or to allow them to be customized for each user. We could have it spell out the full year unconditionally, although if the problem is really that you're not used to seeing e.g. "Dec 25", I'm not sure spelling out the year will help much, since presumably you're rarely seeing both at the same time.
It's happened mostly when I start reading a thread that's been promoted to the top of the latest threads due to a reply, but which was started some months ago. The first messages might have a date "Oct '20" and it looked to me like the date format for more recent messages, such as "Apr 1".
I am used to it now. Apart from the single quote I know that anything more than three months old uses the year, and most I encounter are e.g. from the last half of last year.