I think there is a bug in the Page setup dialog. It keeps wanting to use either an 11x17 paper size, or an undefined custom page size for new files. It also tried using that on some existing files that I opened today that had been US Letter size previously, although I can't replicate that issue now. But v0.99 build 7030 consistently doesn't save the page size even when using the "Use by default" option. See screenshot attached.
Thanks,
Jason