BMS maybe a BS reason, but connecting two chargers is not a good idea. Unless they are perfect sources (balance), plus you are introducing ground loop.
From Quora
Balancing power output is always a unknown path to problems. This is the same as having a power supply with two or more power transistors running in parallel, you need to balance the power and current through them. If you are talking about a DC 12V adapter or so, dealing with 1 or 2A of current each, I would suggest to not correct their wires exactly in parallel. Just use a low resistance resistor in series with each one before you connect the wires together. I would say 0.1 (zero point one) ohm, 1 Watt resistor in each adapter output, then correct the other side of the resistors together (parallel), it would be a better setup then just “parallel” the outputs. The resistors will create a kind of reference of each output for itself, instead of the voltage of one interfere with the control feedback of the other. It works better. Being low value (0.1) it will not interfere with the output voltage.