The Toto Drake is a commercial-grade toilet.
I have seen this kind of thing in action. The clogger claims they don't use too much TP, etc., but the Drake, amazingly, clogs -- and only when that particular person uses it. The reality is that they probably are using too much TP per flush. Having extracted a massive amount of TP from a Drake where the person swears they are not doing that, I'm leaning towards that as an issue. If there's only one person who does it, it's likely operator error.
Suggest to the person that they flush more frequently -- first after using the toilet, then dividing up the wiping session into two flushes. Having given a person this paradigm, I saw this problem solved completely.
The reality is that the toilet is a device, and people need to be instructed on how to use the device. It's not something that we should be ashamed to discuss.
Also, if you're using Charmin Ultra, think about switching to something less cloggy. In the case I describe, this didn't turn out to be necessary with the revised flushing paradigm.
The issue isn't how powerful the flush is. It's how much stuff you're trying to squish through a 2-1/8" pipe all at once. It's not the giant hole that you can see at the bottom of the bowl that gets clogged; it's the much-narrower trapway that you're trying to jam all that paper into that will clog.