"António
Probably it's only a bug, don't worry it will be corrected. Try and check if you actually saved the livery before going out ;)
The livery was definitely saved, as it it on my team page ;)
Could be what Jack said. When I tried it on a friend's account, it showed my livery. So next race (if it still shows a different livery), I'll try CTRL+F5 and see what happens.