UTFT Seven Segment Font leaves pixel traces on 7" TFT

Please help. I'm using a pot on A0 (0 to 5V)to display a value on a CTE70 TFT with a mega 2560. The display values vary from one to three digits ( 0 to 360 via map)) but with the "seven segment UTFT font" I get leftover pixels on the display where it should be a black background. The leftover pixels can be seen until the count goes above 100. Since all three digits are being displayed there are no leftover pixels or the current characters cover the trash pixels. Hope this is clear. When the count goes below 100 the trash pixels can be seen again.Any ideas? Thanks