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I've encountered a rather nasty issue with the UVM 1.2 BCL where changing the `uvm_info verbosity from UVM_NONE to UVM_LOW for the same random seed yields different simulation results. Mantis bug logged here: https://accellera.mantishub.com/view.php?id=5482 This is not good practice, BUT - It is possible for the random stability to be affected, for example, if within the `uvm_info macro, a function is called that allocates a new object or randomizes, thus altering the RNG. Example: `uvm_info("SOME_ID", $psprintf("Some number is: %0d", get_some_number()), UVM_LOW) function int get_some_number(); some_object obj = new(); get_some_number = $urandom; endfunction I understand that some effort has been put in to revamping the message reporting mechanism from 1.1 to 1.2, as well as improving the random stability with the insertion of get/set_randstate guards. If this is something that is completely unavoidable in UVM, then it might be a good idea to add this to the UVM User Guide as an example of bad coding.