Before this happened I think I enabled something in Minecraft or my Catalyst Control Center but I forgot what I enabled but I think that is why it occured im not 50% sure if im correct. But I have some proof of other people having it too its the same as me. But also if the version is lower than 1.8 the hand outline is not there but the character outline is still there but if its later than 1.8 then the hand is affected + the character. It does not make sense to me that lower versions are the least affected. The last 2 is in 1.6.2 as you can see the arm / hand is not affected  but the character is affected. The first 2 are 1.8 and its the steve's butt, the arm is affected with the character as you can see the head is affected way more than the 1.6.2 I hope that this will help you resolve the issue so I can no longer have to deal with this bug or maybe give me a helpful soloution outside of mc thanks.

https://www.minecraftforum.net/forums/support/java-edition-support/1950832-minecraft-graphical-glitch-help-lines-around  https://www.reddit.com/r/Minecraft/comments/7a50ei/white_lines_around_my_skin_any_way_to_fix_it/