Thanks for the suggestions, both of you. I think I figured it out and it's a weird one.
If you schedule a PDF while in the workspace itself, (share - send file on schedule) then everything works beautifully. The workspace panels extend to whole width of the PDF.
However, if you instead schedule the reports via the projects list on the workspace projects homepage (there is a scheduled column with an on/off toggle that allows for report scheduling), it compressed the workspace panels to the middle 50% of the PDF, resulting in smooshed data.
I initially scheduled my projects here, since it was easier to schedule multiple at once. This is probably just a bug as the workspace projects homepage recently had an update
Ohh, I haven't used that feature.. I didn't even realize it was a thing! I've always scheduled from inside the report.
I suggest logging a ticket with Client Care with samples, so that hopefully they can fix that bug!