Has the transmitter ever worked properly or are you trying to get it running the first time?
If it worked before and now outputs 34mA, then it is not regulating the loop current as it should. That's it's job, to regulate the loop current to a maximum of 20mA. If it doesn't do that, there is 99% probability that it is broken and that you need to replace it.
There is 1% probability that a ground loop has been created which adds current to the loop. That could be something like a loop wire with frayed (missing) insulation that touches an ungrounded motor with a winding touching the frame and the differing potentials puts current into the loop. Or water in a junction box, but injection molders typically do not have junction b boxes out in the weather.
The test is to substitute a 4-20mA source (calibrator) and see if the loop current is the same as the calibrator is sourcing.