Is this normal behavior? Expression "contain" shows different results between "single field" and "any field"

[ambivalent.corp]

Hi there, I’m making a simple search box that can search with multiple words. My setup is simple, when the user types multiple words like “red apple” on an input, items with the tags show up on repeating group.

I came across with these behavior differences when I use “contains” in Do a search with “single field” and “any field”. So for example, I have an item with tags field with a list of text which contains “red” & “apple”, with the “single field”, search returns no result. However, with “any field” search returns the item with the tags of “red” and “apple.” I was expecting the expression “contains” will always give me the result and the items with “red” and “apple” tags.

I’m not too sure why they act differently, are they normal behaviors?

[ambivalent.corp]

One more question, how do I constrain filed with “any field” option? I want to search from “any field” but restrict to the fields that I want them to be searched. If I used the “contain” in Do a search with “single field” I will lose multiple words search option due to the problem I’ve mentioned in the first post.