It's hard to tell what effect it may have.
Sure, this may delay N-400 interview, but would you want to have N-400 conducted to only wait longer for I-751 approval? At least there is a possibility of USCIS honoring it and performing combo interview. Could requesting combo interview derail I-751 from it's track towards waived interview? Sure. But nobody knows upfront whether I-751 is going to be approved without interview or require one, whether it's going to be approved before N-400 interview, at the combo interview or after.