rooftop solar unbalancing the grid

I use a contact voltage tester and it went off on a utility box. Just the l owest light on the indicator bar, which isn't serious. There was an electri city line crew at the house next door, so I asked them if there was a broke n 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 invest igating. But he believed it was due to most houses around having rooftop so lar (upper middle class suburb) which unbalanced the grid. I have never heard this before - that too much exported power can cause a n ominally earth to have residual voltage.