Sorry but your answer is confusing: Are you referring to the MPCORecorder error (which I don't have with STKO 3.3.0 and OpenSees 3.4.0)? or to the fact that one of your custom recorder files does not record anything?
If the problem is with the custom recorder, it's because at the end of the tcl line you are using a wrong character. It's not the standard semicolon, but a UNICODE char that is similar to that, but not recognized by tcl (please DON't copy paste character online... )