Some new Leica M10 cameras were shipped with firmware version 126.96.36.199 (most have version 188.8.131.52). It is safe to assume that a new M10 firmware will be released soon.
The only bug I saw so far in the M10 is that the status screen does not correctly display the selected exposure metering mode:
Update #1: the new firmware is rumored to be officially released next week.
Update #2: there are a few more unconfirmed bugs described in the comments section below.