Huanying04

I'm not a English user so please forgive my broken English. I'm new in Mine-imator, I have seen many many Minecraft animation on YouTube or other platform that made by Mine-imator, so I make a try. But when I create a character with my Minecraft skin, the left arm some pixel turn into semi-transparent, I try to find solution on Google or YouTube but there is no any helpful solution or even no same issue on there. I ask my internet friend but he said that he had a same problem that he don't know how to fix it! I posted a pic up here, hope that anyone can help me for solve this problem!