It's not the prefs... The text is set to align to the baseline grid.
Most likely Your text is aligned to Baseline Grid.
Turn it off if not needed.
Definitely the baseline grid. Chiming in, in case you don't know how to turn it off.
If you aren't using styles, select the story and disable it in the ¶ view of the Control panel:
If you are using styles, edit the style and turn it off under Indents and Spacing.
Finally, the purpose of the feature is to align the baselines of a multi-column document. If you like the idea of baseline alignment—which is based on the body text leading value—but want to change the leading, you could leave it on and update the settings. Specifically:
In Prefs > Grids, change the Increment Every to the preferred leading value:
Then go update the leading to match.
Thanks for all of the advice. I appreciate it.