This was a horse (Cliplightning) bred a few hours after the update on preg timers:
[11:26:17] She will deliver in about 10 days.
I would have guessed it was only a "display discrepancy" in how the countdown is counted, except in the mod thread on WO forums, they made a point of showing how the "She will deliver in about 2 days" now showed the lower countdowns (1+n). So maybe the mod didn't find a wundersolution after all
(Obviously i will update if the mare delivers in roughly 3 RL days after all... but i think it is acting like the mod made no change)