Hmm, now that you mention it: inventions did strike me as being at least more irregular since I've upgraded from 1.03 to 1.03b.
Before the upgrade inventions seemed to trigger within at most 5 years or so after discovery of the corresponding tech; since 1.03b they appear to often take far longer than that.
I haven't timed it so it could merely be an impression and it might indeed be simple bad luck, who knows. But still, crucial units and esp. prestige inventions always seem to arrive late since 1.03b

Oh and FYI: I was #1 prestige-wise most of the time, though I did have a couple of close competitors.