Using the /tp command in a command block with relative coordinates. Using a command block in Minecraft Windows 10 edition with the command
[/tp @p ~ ~+10 ~]
teleports the player 10 blocks above the command block itself.

Using the same command in Minecraft Java Edition
[/tp @p ~ ~+10 ~]
Will teleport the player 10 blocks above their current location, instead of above the command block.

This makes it impossible to port certain creations with command blocks between versions, such as seamless teleporting.