We recently bought a new car (2023 Volvo XC90) and installed all of our carseats in it. We have our sons three across in the second row (6 yo in a Clek Oobr, 4 yo FF in a Clek Foonf, and 20 month old RF in a Clek Foonf). The RF Foonf is installed using the seatbelt outboard on the passenger side (my son is 28 pounds already, so no option for a latch install). We are veteran Clek users, have installed these seats RF many times in a variety of cars, and have never had install issues. However, in the new Volvo, the RF Foonf seems to be gradually slipping the lockoffs. I will have a very solid install with much less than 1" of movement at the belt path. Then, after a few car rides, the seat will gradually loosen up until it is moving more than 1" and I have to tighten it back up. This has happened repeatedly over the past few weeks. Thinking it might be a seat specific issue, I swapped that Foonf with our spare Foonf from my husband's car, and am continuing to have the exact same issue. I contacted Clek, who suggested that maybe the lockoffs are worn and should be replaced (they are sending a replacement set) but this seems unlikely given that the same issue is coming up with two separate seats, and this is not an issue in our other car. Any thoughts or suggestions? I love our Cleks and really don't want to buy a new seat, but I'm feeling incredibly frustrated and cannot keep continuing to check and re-install the seat every few days.