Problem with frame breaks

I am engraving BWV 988, the Aria and variations. I have a flow for each variation, and I allow the flow to start on the same page. Suddenly I am up to page 13 and when I manually enter a frame break that music and the page simply disappears. I have been struggling with this for hours.

What could be wrong? Some sort of file corruption? Something I don’t understand? I’m reluctant to post the project here but I suppose if I must I can do so.

Perhaps people know of this issue?

Experimenting after posting, if I just experiment using Engrave Mode to move a bar to the previosu system the hidden page comes back, displays for four or five seconds and disappears. I can only describe this as bizarre. But it’s a total showstopper. What to do?

Dorico Pro, Windows 11 Insider Preview (the latter has not caused any problems before).

The only logical explanation I can think of is that you’ve tweaked the Page Templates (or the frames on individual pages) in such a way that flows are filtered in some or all Music Frame Chains. For instance, it could be that the Frames filter at the top of the music frame on your default page template (or whichever page template is used for page 13) is set to show only some flows, and when whichever variation gets pushed onto the next page there’s actually no frame in which it’s permitted to show.

I could be barking up the wrong Christmas tree, of course - it’s impossible to know without seeing the project.

It could also be that the music following the break is too wide to fit into the width of the system. Under extreme duress Dorico won’t manage to draw anything at all in such circumstances. If you could attach the project here, we’ll be able to say for sure.

I solved it. I had to flag a request to delete the post, for some reason Discourse would not let me,

Sorry to waste your time.

After working on it for a few hours trying random things I found the last page template was not the one I expected. I reassigned it and all came good. I don’t think this is a bug, but it may be. I never touched the page templates after making a custom first. Perhaps having new flows start on the same page when they can, not throwing a new page, may be somehow related. I have no idea. I achieved this before reading any replies here, so @pianoleo you are sort of right. All very odd.