WP.com editor occasionally shows only my old .com site… ARGH!

I regularly write/edit from a computer that doesn’t allow access to WP Admin since my site is alcohol based (stupid work filters). The workaround I discovered is to use the WordPress.com editor linked to my site (which is on an a different server). I’m not even sure what it’s called, but I access it by going to https://wordpress.com/posts/domain.com. It works great when it works, but for some unknown reason, it randomly pulls from my old wordpress.com blog and doesn’t show the info that’s on the SiteGround server.

I’ve tried a bunch of suggested solutions including changing the old blog name, but it still happens all the time. While I’d prefer not to, I’m on the verge of killing the old blog in hopes it fixes the problem. Any help would be very much appreciated!