STLLoader errors loading files on slower PCs

I’ve been trying to create simple app to display my STL files for printing. It works quite well but some models which have around 30mb bugs out, on more powerfull PCs it works for models as big as 120mb but sometimes it bugs on even 40mb ones. I’m using same technique as in three.js webgl - STL

After some digging I have found that it sometimes just changes Geometry values to NaN, without obvious reason. It all happens in loader. When i try to debug loader the data seems fine. When it comes to callback there are NaNs.

Has anybody dealt with similiar situation? Is there a fix? I guess its browser problem. On both PCs i use Chrome and Chromium. (Also tested on chromium based facebook browser on a phone and samsungs internet which works. Mobile chromium also bugs) Mozzilla is same story.