I play minecraft on playstation 4, in a realm. Command block settings are activated. In every command block with the command /execute created before the new update doesn't seem as a correct syntax. As an example I can take "/execute at @r run setblock ~~~ gold_block".

The errore seems to be in "@r", but rewriting the command it works without problems. Do I have to rewrite every command block where it was written "/execute"? I hope not. 

I can't say if this problem affects also normal world because it is just with commands written before the new update, so I can't try it creating a new world now.

Steps to reproduce:

Enter in a world where there is a command block with the command /execute already written (before the new update) and try to activate without changing any letters of the command (you will see that it is considered as an error);

Then try to change just one letter in order to create a real error of the command (now you will see the new error detected);

Rewrite the original command (the same as the one in the first phase) (cancelling the error you wrote in the second phase) and try to activated the command. The command will work succesfully now.