The following 2 paragraphs are quoted from: https://www.thoughtco.com/puta...ould-grammar-1691554
1, In English grammar, putative "should" is the use of the word should in contexts that indicate surprise or disbelief, or that refer to the occurrence (or possible occurrence) of some situation or event. This usage differs from the should of obligation (i.e., the mandative "should").
2, In addition, putative should "occurs in subordinate clauses as an alternative to the subjunctive after expressions of suggesting, advising, etc.: They insisted that I (should) stay the whole week" (Oxford Dictionary of English Grammar, 1994).
I think these 2 ideas contradicts to each other, because the usage of should of the example sentence in the second paragraph is defined as "putative should" there, but, by expressing obligation, is thus defined as "mandative should" according to the first paragraph and differs from the putative usage.
Is my understanding correct that they really contradicts to each other？
Thanks in advance.