Ambiguity of "quite"

Solution 1:

No, you're not missing anything - the word has ambiguous definitions.

Solution 2:

When it's used with an absolute, like correct or complete, people generally mean #1 or #2. When someone says, "Quite nice, I'm sure," watch out.

Solution 3:

"Quite!" as in, "Hear, hear!" or "indubitably!"

There is a distinct bias toward the opinion of the speaker with this word usage. It implies "completely" while simultaneously allowing for factual refutation:

"He was quite close to falling off the cliff!"

"On the contrary, he was several feet away from the cliff. He was quite safe from a fall."

"Being so near to the cliff is quite the same as having nearly fallen!"

"Quite so, and yet he was never at risk for having fallen."

In this exchange, the opinion of the first speaker is that the object person was very close. The respondent begs to differ, asserting the object person was very safe. The initial speaker counters with a circular reply. The respondent refutes the reply by agreement.

The term "quite" is not an absolute, it is a conditional that implies conditions nearly identical to certainty, yet lacking certainty.

Solution 4:

Many languages have words with more than one meaning and English is no exception. That is without considering tone. English is made more difficult by the geographical spread of the user base leading to words having different meanings in different cultures or locales, including between England and Scotland.

Considered from a standard English English perspective, your examples 1 and 3 give the two meanings normally attributed to the word "quite", however in example 2 you mix both, as "quite sure" would come under example 1, while the others would come under example 3.