SFDC Validation Rule Error Messages and Tab Sets

Would you mind checking to make sure that your themes are up to date? If they’re not, then on the Themes list page, you’ll see a button to update out of date themes. If you see that button, I’d recommend going ahead and performing the update. Also, does the issue occur when you’re previewing the Skuid page directly, instead of in this Home page override?

I’m not sure how your conditional rendering is functioning, but it sounds like the conditional rendering may be relevant in your case. If components are being hidden at the time when the validation errors are added to the page, the errors may also be hidden.