Hi everyone! The description of this bug might sound kind of strange. I tried to explain the bug the best I could in a few words but couldn't really do that effectively. 

The bug that I'm reporting today is very strange. I just barely updated Minecraft (Bedrock) to "1.13.0". This came with quite a few bugs but I am reporting to the most prevalent bug in my opinion. 

Now I'll explain the bug and how I found it.

I loaded up Minecraft this afternoon and started to load up the realm that I play on (I am the realm owner). The loading screen gave me a prompt to update Minecraft because 1.13.0 had just released. So I updated the game and reloaded Minecraft and loaded up my realm. After I had logged into my realm my brother (Another realm member that uses Pocket Edition on his Android phone) also logged on. We played around with the new skin editor for a bit making new skins and such and decided to load our old custom skins that we had made prior to the update. When we each loaded the custom skins I realized that my brother's skin appeared to be my custom skin. He couldn't have actually had my skin on because he doesn't even have the skin file downloaded on his phone. He also saw that my Minecraft skin appeared to be his custom Minecraft skin, which I also do not have downloaded on my laptop. 

I thought that this was very strange so I did a little bit of experimenting. From my experiments it seems as though this problem only applies to custom skins. (For example, if I were to wear the default skins or a skin that I created in the new skin editor, my brother would see that actual skin...not his own. The reverse is that same as well).

In addition to the appearance of having the same custom skin, when I tried to reload my custom skin, after selecting the skin file, the game gave me a prompt to select which skin format was correct. There were two options, the "Slim arms" option was my skin with slim arms. The other option was my brother's skin. So I selected his skin and exited the pause screen. When I went into third person, I had his skin on and he appeared to have the same skin on. 

After this, my brother changed his skin to a different custom skin (Floating Troll Face) and he appeared to be the troll face. I however did not appear to be a troll face from either perspectives. (My brother's screen & my own screen). I have a few screenshots attached to show these issues.

I have a theory trying to explain what went wrong on the coding end. (Disclaimer! - I haven't been able to access any of the code of Minecraft. This is just a theory based on some of the knowledge I have of coding.) Also, I don't know how to code in C++.

My theory is based on the idea that there is a Boolean that controls whether a custom skin is attached to a player. Based on that Boolean there are two different actions that could happen. 

(1.) Var Custom_Skin_ID;

      Var Normal_Skin_ID;

      Var Custom_Skin_Equipped;

      Custom_Skin_ID = (); //The players custom skin that they want to equip.

If [Custom_Skin_Equipped = True] {Display (Custom_Skin_ID)};

//Displays custom skin on any player that Custom_Skin_Equipped = True

If [Custom_Skin_Equipped = False] {Display (Normal_Skin_ID)};

//Displays Normal skin on the player that has Custom_Skin_Equipped = False

Again, this is just a theory of what might have gone wrong in the code. I understand that C++ syntax is different than this and that the developers may not have even used this logic to code the new skin system. I also realize there are a few flaws in the code written above such as the "ID" variables not being assigned. This is just an example so I didn't feel it was necessary to assign those variables a value.

I hope that this bug report will help in resolving this rather strange bug. If you have any more questions concerning this bug just let me know in the comment and I will answer your question the best I can. Thanks everyone!

[Edit] Just thought I would link this bug report because it sounds quite similar. 

3. MCPE-54453