I use RO-filtered water and for fun we safely discovered it does flash boil in the microwave.

I use it in a proper glass tea kettle though. It stay clean for months now, it used to get messy in a few days using tap water. I also think tea steeps tea better in low TDS water. From an osmotic point of view, that makes sense.

Normally our tap water is nearly liquid tums 😅

Ironically, your problem is that your jug is too clean. Do a less good job washing up and there shouldn't be any danger.