Blue and red circle cross out

That's not a glitch, it's an effect of a lot trait called Breeding Ground. It works like On a Ley Line does for Sims, it gives the chance to increase the size of the pregnant pet's litter. The half red/half blue circle with the x means it's being activated. I've seen the same symbol under my Sims that stay home to give birth. 🙂

~Tyger <3