Currently, "These words" and "Not these words" are treated differently than "One of these words" or "Exactly this text". The reason is that the first two allow whitespaces as seperators, whereas the other two don't. Also, stemming is applied in both cases.
However, it seems confusing that those seemingly similar fields behave so differently.
Find a way to make the four fields behave similar, all reacting on comma as a seperator, and having a placeholder that explains its usage.Change the field behavior as shown in the mock.
 There are no placeholders for "These words" "None of these words" and "One of these words".
 There is the placeholder indicated in the mock for "Exactly this text"
 "These words" "None of these words" and "One of these words" create pills on comma, whitespace and enter
T "Exactly this task is an offspring of T173563text" behaves exactly like the main search bar technically