I have an HTML page that loads one way the first time you load it and another way the second time. This is reproducible using Chrome in private mode (because it clears the c
Some main issues to look into. Browser size. Is it wider at one point than the other?
It's obviously within the same browser but just in case, I would test this in multiple browsers, because you do want your code to be cross compatible.
To me it looks like a width problem.
Perhaps you have a #login div, or some oddly named, at the top right that contains that content and floats it, and being that the content is not responsive, but the div itself is. When the div shrinks a little the content itself doesn't and pushes the rest of the content down.