Yuck. So - I often have this problem on my main monitor, and a restart usually fixes it (the resolution for InfoPath ONLY goes wonky when I dock / undock my laptop from my larger monitor) but I haven't yet been motivated to find a way to handle it other than restarting, since we mostly use browser forms internally and I haven't been doing any new design work. Do the PCs where it works have the same operating system / updates than those it doesn't? InfoPath Filler uses IE for rendering and I know that the text settings in IE affect size of text in InfoPath Filler, but it sounds like in this case text isn't the issue. https://www.infopathdev.com/forums/p/39134/119481.aspx suggests that on Windows 10 they needed to change the scaling on the machine to 100, which you could check and see if it helped (although, as someone with glasses who needs to have things scaled larger, I know that isn't very useful for many of us).
Hilary Stoupa
