Whenever a unit is being built (with nanoframe on screen) units randomly show bits of nanoframe around them which do some strange things like rotating around a stationary unit.

OS: Windows 7
Graphics card: ADM Radeon HD 6490M

Just saying that I have never seen this bug. Does it happen with every nanoframe? Have you tried older/newer drivers?

Since posting, I have realised that when playing spring my laptop uses the power saving intel HD graphics card (it has switchable graphics).
If I force it to use the AMD card, the game has a load of horrible glitches.
As for this glitch, the anomalies will only show if there is another unit/building being built on-screen (with nano-frame showing).
It doesn't happen to everything on screen, just one or two at a time but almost all the time.