I've seen that happen. A lot, actually! I've had players insist that a spell doesn't have a Saving Throw when I ask which Save it is, and read it multiple times like you describe, until I take their sheet (I make sheets for players that have the full text of spells, shortened to reduce word-count, but still maintain all that it does) and read it myself, only to discover, it says right there it's a WIS SAVE (or whatever).
I agree with you that they're not doing it on purpose! It's a strange phenomenon.
Like I don't judge our OP for the trouble they had (even if I disagree with their conclusions), I don't judge the player for it - but it can be a tad frustrating!