I get it on the lappy... GeForce 8400M G...
It seems to go away at certain sizes, like 128x128, but it's there on most other sizes, even with increments of 32.
Well i was messing with the cap and for the Titled Background that is 4x4 is messing up if its not:
Size in power of 2n. (sounds like tearing problem in textures)
Edit: But only in zoom 200,200 if i take 300,300 then its always ok!!! same goes for 400,400 as broken and 500,500 as ok.