Deleting a step from steps tab, without removing page inside it causes error

[JessicaFrank]

Author reported gray screen upon Previewing GI in prod author and on LHI.

Downloaded interview from LHI and tested it on author prod. I could replicate the issue with the following errors in the console when previewing from 1-Introduction

Opening interview in author didn't show any wonky logic or broken variables. All page paths seemed fine. However, there was an "unknown step" after step 6 in the pages tab. Steps tab only showed steps 0-6.

Theory is that author deleted step 7 from the steps tab, but had already put a "new page" into step 7 at some point. Because Step 7 had a page in it, it couldn't be fully deleted from the steps tab. So when the interview loaded in preview mode (and in the viewer on LHI), the steps structure didn't match up between the truth of the steps tab and the truth of the pages tab, causing the error shown above and a gray screen to appear.

When I deleted the page in the "unknown step", it disappeared and looks to be actually deleted. The interview loaded fine in preview mode and I asked the author to confirm that it's running as expected.

[tobiasnteireho]

Observed again today from different user. Awaiting details.