Comment 1 for bug 1600642

Same here, but on a laptop (Thinkpad X1 Carbon Gen 1). MATE 18, upgraded from 17.3.
> inxi -G
Graphics: Card: Intel 3rd Gen Core processor Graphics Controller
           Display Server: X.Org 1.18.3 driver: intel
           Resolution: 1600x900@59.97hz
           GLX Renderer: Mesa DRI Intel Ivybridge Mobile
           GLX Version: 3.0 Mesa 11.2.0

For me, it only happens after resuming from suspend (and only occasionally). Also, fonts in xterm are not affected (but those in mate-terminal are, along with most of the rest of the interface).