Reply To: Same space between words

Your Justification settings are way too strict! InDesign needs at least ONE of those three items to be variable to justify text: either word spacing or letter spacing or glyph scaling (where that last one would be “yuck”).

In your case, you should indeed set only Word Spacing to the same values. It is likely that your contradicting settings make InDesign go ‘shrug’ and just ignores what you tell it.