Your water heater has a leaky heater coil. Replace both heater elements immediately. The ground being loose allowed the voltage leak to not be grounded out.
So you fixed the safety system, however the jacket to the heater coil is shorted out leaking electricity into the water. That you have not fixed. You most likely have bubbles showing up in your hot water because that voltage leak is hydrolyzing water into hydrogen and oxygen inside your hot water tank.
You will also save some money because water heaters break the circuit to only one hot lead when the water reaches temp. Because of that the current will not heat water BUT IT WILL STILL LEAK OUT OF THE BAD COIL into the water, then flow out the ground wire.
Waste of power and it will rot out your water heater digging holes in the tank by galvinisation.
So, service the water heater.
I don’t think so. The (tankless) heater is (was) brand new. When I measured the current between grate and showerhead when it showed 110 VAC I was only getting a few mils. I refreshed the ground spike connection and created a heavy 4-position jumper that connects input cold, output hot, on both sides of the flex dielectric connectors. The ground spike fix alone stopped the big volts between grate and showerhead. Now the voltage between grate and head is only about 1.5 volts whether the water is running (meaning the heater is working) or not. If I had the short you’re thinking about I’d think I’d have huge current flow and about 60 watts of heat.