Header shifting position

Hi everyone, I am designing a site in Local/Flywheel with the Twenty Twenty-Five theme.

I use “Header with large title” on Front Page (Home) and “Header” for a template I designed for two other pages (About and Contact).

All is fine navigating between Home and About, which have different headers/templates. When I select Contact, however, the header (footer as well) moves slightly, but perceptibly, to the right, although About and Contact share header/template. I wish header (and footer) stayed put.

Thanks for any suggestion. Pease note that I have no coding ability.