Can Any of Our Readers Assist Here?

On p.113 of Rabbi Dovid Landesman’s “Food For Thought“, he relates Rabbi Yaakov Kaminetsky zatzal once discovered a major halachic error in a well-known Acharon based on a simple Hebrew grammar mistake.

Does anyone know what this refers to?

In a footnote on p.116, Rabbi Landesman mentions “Shiurei Da’at” as the source for Rabbi Bloch’s remark on Agudat Yisrael waiting
for Mizrachi’s statements before it could form its own views.

Where in Shiurei Da’at is this found?