'Conspiracy' plot hole
 

This one has bothered me for decades. At Crickhollow when Merry spills the beans, he says that it began the previous April when ":things got serious", and names Sam their "chief investigator" and says he collected "a lot" of intel, until he was caught and clammed up.

The problem with this is that there's no timeline in which it works. On April 13, Gandalf tells Frodo about the Ring. Sam overhears; Sam is caught. No window for Sam to be gethering and reporting intel- Merry's story just doesn't work.

Perhaps it wasn't the first time Sam was dropping the eaves.

This problem bothered me too. The only apparent solution is that Sam's drying up did not include reporting the conversation from The Shadow of the Past. At the end of the chapter, we see this:
If Sam wanted to interpret this interaction narrowly, he could reason that his punishment for reporting the conversation was to be sent away with Frodo, which was already happening anyway.

According to Merry: This is at least consistent with the theory that it was the collecting that stopped, not the reporting of already collected information.

We also know from the conversation with Gildor and the Council of Elrond that Sam was not above eavesdropping even after being caught.

Welcome to the Barrow-Downs, Bingo.

You provide a rational explanation for William's plot hole. If Sam passed on what information he had and simply stopped snooping, this might explain the inconsistency. Of course, by that time there was nothing left to snoop about. The Ring had been explained and the decision to take it from the Shire had been reached.

Thank you! It might be true that there wasn't much left to learn from spying, but the conspirators couldn't know that, and Gandalf did hang around for two months before he left. One thing they could have learned if Sam had still been spying was the exact timing of Frodo's planned departure. When it happens, they are prepared, but by then it wouldn't be so hard to guess what was going on given the timing and the fact of Frodo selling Bag End. If he had left sooner they might have been surprised.

Could be.

Like you, I tend to try to resolve all questions regarding Tolkien's published writings in favor of consistency. Your theory would potentially resolve the inconsistency. Of course. there are others here who might simply say "he made a mistake."

There's a thread below, "Seriously - what was it that scared Gandalf to look more into Bilbo's ring?" that also addresses inconsistencies in LoTR, with the same two viewpoints taken.