That's because of the low profile TrackPoint. The upper notch on the B key is larger than it was on older ThinkPads with the high profile TrackPoint.
This is nothing new; every recent ThinkPad with the low profile TrackPoint has the B label offset like this. It's not something you notice when actually using the machine: I've been using a ThinkPad Yoga 460 for most of this year, and never realized the B label was offset until I saw people talking about it when the T25 keyboard photos were leaked.
Unlike the high profile TrackPoints on all my previous ThinkPads, the low profile one never leaves a smudge on the screen. I'll take that over a perfectly aligned key label any day.
-An sxga+ (w/led mod) x61s owner.
No banding on the bottom, accurate colors, and great brightness.
EDIT: For those who do not want to google it themselves: https://forum.51nb.com/forum.php?mod=viewthread&tid=1699442&...
Just so I make sure I understand you correctly: you're complaining about the positioning of the label on the key (since it has to be shifted due to the notch caused by the trackpoint)? That is, you're not complaining about the key itself, merely the label?
51nb.com (chinese thinkpad forum) has been doing better work with less resources by putting updated motherboards into classic thinkpad chassis. (see X62 for example)