Keep in mind that The Sims 4 Studio might also release a batch fix for this (still being investigated, though). Not all chairs are affected, so you will have to test your chairs and choose the ones you want to apply the fix to.
Sims 4 CC Chairs hotfix after March 2021 update: DIY style The routing bubble will appear above a Sim’s head if you try to use the CC chairs slotted into a dining table. At first glance, it seems as if the issue is only impact dining chairs and only when dining chairs are slotted into a table.