This is weird. I clipped the page again (so now I've got two notes, should be identical). When I search All Notes for dehumidifier, BOTH notes are in the search results. But no highlighting to indicate where EN thinks that text is located. Again a search and replace doesn't find the text.
Obviously "false positives" are OK, if time wasting. However, "false negatives" would be a problem. Maybe I've got a setting somewhere that's causing this, but I can't think what it would be.
I may uninstall/reinstall EN to see what happens.