The two upgrades of TrueOS I've had have messed up the rendering of icons and I am also seeing the same issue when using qpdfview. The symptom is that icons, and now pdfs, look very pixelated, like they are being displayed on a Nintendo. Chrome can view a PDF just fine, so perhaps it's a QT issue?
I experienced this on STABLE and now I'm on UNSTABLE with the same results.
Is anyone else experiencing something like this? I don't know what other information is valuable to include so feel free to ask.