Thruster Wire Burning?

I have completed my build of the BlueROV2 and during the software setup stage, after testing the thrusters, noticed some very minor yellowish/brown discolouration on the thruster wires. The discolouration was close to the terminal block on the penetrator side connection. No excess heat or burning smells were noticed and the discolouration is extremely minor and does not appear to penetrate to the wire. It did not appear to get any worse after a secondary test and the thrusters did not run for any prolonged length of time. Is this okay or will it be an issue?

This sounds fine. It may be an artifact of production, the wires are tinned in a solder pot (we dip them in a hot vat of molten metal).