Can't select sims to go on vacation

[Lailantie]

Product: The Sims 4
Platform:PC
Which language are you playing the game in? Deutsch
How often does the bug occur? Every time (100%)
What is your current game version number? the latest
What expansions, game packs, and stuff packs do you have installed? Seasons, Gartenspaß, Laundry Day, Romantic Garden, Vintage Glamour, Go to work, Island living, wellness, cats and dogs, outdoor (the one with the rentals)
Steps: How can we find the bug ourselves? Have a household of 8 sims/pets and have only a few of them go on vacation and try to add members of another household
What happens when the bug occurs? Whenever I want to travel with some of my household/family, the game sends ALL of them, even though I don't choose them in the list and their pictures are not green. I can not select a number of household members lower than everyone. I only can go alone, that works, and then add household members by inviting them one by one. In addition, I invited two sims and a dog of a second household that I also play. I could assign the beds to the two sims on day 1, but they weren't there. On day 2, the dog of household 2 arrived, later the woman, the son never made it.
What do you expect to see? I want to be able to choose the sims that I want to go on vacation with and I want to have them travel together to the spot. I also want to have the butler stay at home and take care of the toddler and not follow me on vacation.
Have you installed any customization with the game, e.g. Custom Content or Mods? Yes
Did this issue appear after a specific patch or change you made to your system? No

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This has happened everytime with every vacation. In the past I used to leave the cat at home and for some reason the cat always showed up at the vacation place. I thought I might have made a mistake and placed a cat toilet in the vacation home just in case, and next time the cat was again on vacation. Still I didn't realize there was a bug until I came across the situation above. It worked fine when I went from a household with three sims and a dog, I could send only two of the sims, a dog, plus two sims of another household together on vacation. But whenever I go from a big household of 7 or 8, it won't work to select a few.