Pavlovia survey appears truncated in design tab but participant URL works fine

My supervisor has a survey on her pavlovia account that has been used in a previous project about one year ago, I think. It worked fine then, and the participant URL continues to present as expected and collect all data properly but in the design tab all but the first page is gone. This is true for both the edit windows and preview windows and the JSON code shows this also. But, as I say, when using the URL to share with participants all works fine, so there is clearly some mismatch here. I have copied the survey onto my pavlovia account and it all works in exactly the same way.
Does anyone have any idea what is causing this and how I can fix it?

If the issue can be replicated by sharing the JSON, please could you PM it to me and I’ll take a look.