@VapeeVixen
there are signs if a party may not have enough to do. Parties that show your sims with work or hobby activities , good chance the person throwing the party has a larger house and more activities to interact with. These parties usually level up
If the person who is throwing a party starts the party and does not interact with the party goers, the party may not reach level 10. Party goers and the person throwing the party both need to do their share of interactions to get the party to level up to 10. Some players throw a party, leave the game and rely on only the party goers to level up the party. If I throw a party I always interact with party goers so all my parties level to 10
EA has been having issues with party freezes. They patched the game yesterday. If you have already patched your game and still getting freezes, please report those to the bugs mobile section