I was viewing the Stack Exchange Winter Bash Leaderboard and I noticed that I've apparently only had my account for six months, which is news to me... I opened my first site account here in February of 2014.
My account is much older than this, what's causing this bug?
To add some detail... On the per-site list, it does line up the "member for X" text with my actual membership time on that site. For example, when I look at the Meta Stack Exchange leaderboard, it shows me as a member for 2 years, 10 months. This is expected.
With some work, today, I've managed to exceed my Interpersonal Skills hat count of with my Meta Stack Exchange hat count. This has changed my account age to match my MSE account age...
Still not reflective of my actual age... but better.