Orange particles appear on chair I already claimed

After claiming a seat in CoMC, the green particles on the chair became orange, and I could “swap” to that seat. In a Potions class, clicking the orange particles makes them disappear but it says “You’ve claimed this seat!” This does not seem to have any order to when this bug appears. Just every so often when I claim a seat, the orange reappears.

As you can see in this screenshot, all seats show orange particles, including the top left seat, where I did not reclaim, but the class did start for me.
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As you can see here, the particles appeared, and I could claim it again.
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