I agree it feels out of place in that list. Most of the rest of the principles are prescriptive: "Do this" or "Take that action" or "Keep this in mind", whereas this one is an after-the-fact measurement. The rest of them are things you can wake up one day and decide to incorporate into your life. "Being right" is not such a thing. They should probably re-write it with something like "Use good judgment" or "Seek diverse perspectives."
"They seek diverse perspectives and work to disconfirm their beliefs."
Which is very sensible, but then the principle would be "[Our leaders] Do not assume they are always right".
The wording of this principle is probably the one that gets talked about the most internally. People always bring up changing it, but when they rolled out a new revision of the principles two years ago or so, this one stayed the same. It's a shame, because once properly explained it's probably one of my favorite principles.
It's not the only one, though. The last four are either commands ("Dive Deep") or a completion of a sentence starting with "Leaders" (e.g., "Leaders dive deep"). But "Frugality" and "Bias for Action" are just properties of good leaders. The tenses (or parts-of-sentence) are all different.
We used to have "vocally self critical"
It's a characteristic ("good judgement") rather than a principal, agree it makes no sense whatsoever being on this list.
Hire competent people.
If you're "wrong", a lot, then you're probably not the right fit for that job.