I'm not sure if it's intentional or not but this is what some online stores appear to do (poorly). E.g. suggesting me office chairs after I just ordered one, suggesting motherboards incompatible with a CPU I'm looking at...
If you're seeing ads from the same company for office chairs it's most likely a poor marketing campaign setup. It could also be if you're running third party blockers in your browser when you check out and then use the mobile apps you might not have been counted by the Facebook pixel.
"Oh that's because they set their campaign up poorly, they should have done xyz" yes but they didn't - a statement that holds for most campaigns we encounter. It is the ad-tech equivalent of "just don't write code that does <insert unsafe behaviour here>". It's a flawed argument, because demonstrably, in the vast majority of cases, people simply don't.