Here's a picture of it happening with fear.
Is the texture square or rectangular? That bug happens a lot with custom rectangular textures.
If square, change them to rectangular.
Also, add a few 0s at the end of your file and add 1 digit to your texture length. For example, if your texture has 12 characters, change it to "13". If your texture is 24, change it to "25" and so on.