Game freezes for a few seconds

aey1jj594l0m​  Yes, the problem could be because you used a house from the Gallery.  Some of them broke when the pre-For Rent update was released, and more have broken since then.  You could test this by moving your sims to a different lot, one made by EA and not modified in any way.  You don't need to save your progress; this is just a test.

When I said test a new save, I meant click New Game, create new sims (NOT from the Gallery), place them in a default house (NOT from the Gallery), and see whether the same problem happens.  The idea is to find out whether the problem is limited to your save or is more widespread.