I was chatting with some friends a couple of days back about why ChatGPT famously seems to think that "salmon" is a word with a silent "v" in it (if you ask it for a word with a silent "v" in it it will commonly respond that "salmon" is an example).

One of them came up with a theory that "salmon" is simply a commonly encountered word when talking about unusual silent letters in general, since it's got a silent "l". So ChatGPT is asked about a weird silent letter, the word "salmon" pops up, and it shrugs and thinks "guess salmon has a silent v in it." Since it doesn't "see" words as collections of letters it has no idea there isn't a V in there.

Perhaps this is a similar case. It sees the word "spam", that triggers its "this is a bad topic, I shouldn't be helping with this" reflex, and then it needs to tell the user why it's a bad topic and comes up with health concerns because it realizes it's talking about recipes.