This is effect of

os.setComputerLabel(string.char(1,149,153,200))

On a turtle. When picked up it stays on label. Same thing with pocket computer names.
Probably not a bug but a unpredicted effect.

Yeah, the custom glyphs that ComputerCraft renders in place of the Control Characters are non-standard, so they'll inevitably look different when rendered in a different font (you'll see a similar thing if you write those chars to a file and open them in an text editor). I could strip them out when setting labels, but it might be better to leave them in to demonstrate a point :p