In case you are using an expression in place of X and Y coordinates, make sure the syntax is correct and in case you are using a variable, make sure you spelled the variable correct. Usually you get 0,0 if the expression is incorrect, or in case the variable does not exist, so GDevelop return 0 to avoid the game crash but obviously it may cause unexpected results like in your case.
In case you are using pure number in place of X and Y, I personally never experienced this problem. Can you show your event?