In a recent question (since deleted), CDO (Cambridge Dictionaries Online) is shown to give the following examples for (intercategorial polysemes of) since:

since adverb
B2 from a particular time in the past until a later time, or until now:

Emma went to work in New York a year ago, and we haven't seen her since.

He started working for the company when he left school, and has been there ever since (= and is still there).

I've long since (= long ago) forgotten any Latin I ever learned.

More examples

Hostilities between the two groups have been in abeyance since last June.

Roz has adopted one or two funny mannerisms since she's been away.

...

Their movements have been severely circumscribed since the laws came into effect.

Your piano playing has really come on since I last heard you play.

Some would argue that all these usages should be classed as 'preposition' usages, and I'd certainly class 'since last June' as a prepositional phrase, but I don't think anyone would argue that the second group of examples should be classed as 'adverb' usages.

(To be fair, another 'version' of CDO seems to correct this error.)

Do people know of other obvious (rather than debatable) errors in respected works (grammars, dictionaries, and perhaps over-dogmatic style guides)?