Pat, I noticed this exact same issue about a month ago also in a client org. Pretty sure it had to with upgrading to Brooklyn.
Matt Brown, in my case, yes it was an old page that just stopped working.
Pat, I did find a workaround however, see the video below:
This issue may have been related to a bug that has now been resolved in the Brooklyn (10.0.4) Maintenance Release and the Brooklyn (9.5.11) Maintenance Release which are now available from 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 We also recommend that you update out of date themes when you upgrade.