Sure. But the level of description that you're giving in an interview can be pretty generic/non-proprietary. If that wasn't the case, then you really can't reuse any knowledge from job to job and that's just not so.
Sure, every company is going to have their 'special sauce' components, that ARE proprietary, but nobody's going to expect you to unpack those.
I doubt it's common, but my friend had an experience where they kept trying to direct him towards specific technical topics of particular interest to the business.
He worked for their competitor, but not in the capacity the interviewer was trying to delve into, so in addition to scummy, it was pointless and annoying.
Sure, every company is going to have their 'special sauce' components, that ARE proprietary, but nobody's going to expect you to unpack those.