files not updating properly

I’m running into a weird issue and think it may be something with hosting on Network Solutions but not sure, and wonder if anyone has ever run into this issue. I’m making updates to the CSS file, uploading it and seeing the changes in the WP editor. But some of the pages are updating and others are not. I’m using a couple of different page templates, but they are all using the same header and CSS files. I’ve tried it in different browsers and different computers with the same results. There are no cache plugins installed. Any idea what’s going on and how to resolve it? Is this something with the hosting or another issue?