I used codes for physical copies of expansions of the Sims 3 (pets, ambitions) but I have an issue..

"SimplyJen;c-16393429" wrote:
Can't say I know of the Pets glitch... Currently playing with 6 of them in my legacy household (7 if you count critters). However, integrated cards will not render pets properly. For this pack, it is recommended to have a dedicated card.

According to the "Nightmare Fuel" page for The Sims on TvTropes, fast-forwarding too much could possibly do the "stretchy" glitch for the pets where they get all long and distorted. It never said how rare/common this is, or if it only does so with various graphical cards etc...