I have a string 'Ranjith Jose' in column 'Name', which has double space between first and last name. I have used Replace prepare recipe.
Matching Mode: Regular Expression
Normalization Mode: Exact
\s+ --> No Value (I need to keep one space instead of 'No Value'.)
the Find&Replace step used to trim and ignore whitespace on replacements until quite recently, so if you aren't on a v9.0.3, it's probably the expected behavior.
You should use a "Formula" step, and use replaceChars() or replace(), like
strval("Name").replaceChars(" ", " ")
strval("Name").replace(/\s+/, " ")