Nav component items display as three lines with no label sometimes on page load. Doesn't seem to have a pattern. Once clicked, the icon and label appear. Screenshots attached.
This has been addressed in the new Millau 11.2.6 release which is now available on the Skuid Releases page.
As a reminder, Salesforce does NOT allow reverting back to prior versions of managed packages. Skuid always recommends installing new versions in a non-business critical sandbox environment to test all mission critical functionality before installing into a production environment. We also recommend that you update out of date themes when you upgrade.