Multi-page forms more than two pages long - what am I missing?

[fsrtechnologies]

I clicked through to the REPL example of a multi-page form, and just for the heck of it I extended it to three pages (copied Page2 to Page3, made a few cosmetic changes) but I run into an odd problem: if I fill in the fields on each page and Submit at the end, "Submitted data" only includes Page1 and Page2. To get Page3 to submit, I have to click Previous Page, then Next Page to get back to Page3; now, all three pages are submitted.

I'm sure there's something obvious that I'm missing, but... I'm still missing it. Here's my updated REPL:
https://svelte.dev/repl/1ed049d573cd43b4bd1e9248a91e85c9?version=3.44.2