rooftop solar unbalancing the grid

[Falscher Bruce]

I use a contact voltage tester and it went off on a utility box. Just the lowest light on the indicator bar, which isn't serious. There was an electricity line crew at the house next door, so I asked them if there was a broken neutral in the street (which often causes an earthed item to go off). The bloke told me that the resident has reported a tingle and they were investigating. But he believed it was due to most houses around having rooftop solar (upper middle class suburb) which unbalanced the grid.
I have never heard this before - that too much exported power can cause a nominally earth to have residual voltage.