Did the leading scholars of Islam find any major shirk in the books of Al-Nawawi and Ibn Qudamah, or are the claims of their promoting major shirk or seeking intercession through the Prophet after his death lies intended to tarnish their reputation?

Al-Nawawi and Ibn Qudamah are two great imams and prominent jurists. The Ummah has unanimously praised them and benefited from their knowledge. Al-Nawawi has some deviations concerning the chapter of Names and Attributes, but neither of them fell into shirk (polytheism). What they mentioned regarding tawassul (seeking proximity to God through an intermediary) and the narration of al-Utbi is not shirk, but rather an innovation (bidah). Shirk is asking from the dead and seeking their aid, and they did not say that.

Ibn Qudamah presented the narration of al-Utbi with a weakening صيغة (formulation), while Al-Nawawi approved of it. This narration is false and has no isnad (chain of transmission), and it does not involve istighathah (seeking aid), but rather seeking forgiveness from Allah and intercession through His Prophet, which is tawassul through the personage, and this is an innovation, not shirk.

Scholars who have a truthful tongue in the Ummah may err in their ijtihad (independent reasoning), and their error is forgiven. They are not to be condemned as sinful, let alone innovators or disbelievers. Sheikh al-Islam Ibn Taymiyyah holds that scholars who have praiseworthy endeavors and righteous deeds, and who made an error due to a foundational ambiguity, are forgiven by Allah for their mistake.

Sheikh Al-Albani said: It is not permissible to withhold mercy (i.e., not to pray for Allah's mercy) from Muslims, neither their common folk, nor their elite, nor their scholars. It is not possible to rule that everyone who falls into kufr (disbelief) or bidah (innovation) has kufr or bidah attributed to them. Among the grave mistakes is that committed by committed youth who fall into violating the Book and Sunnah unknowingly, while Muslims do not intend innovation nor do they stubbornly reject evidence.