Unfortunately, the gauge in the energy dashboard does not take solar energy into account.
Right above, wrong below in gauge.
Greetings Peter
It is actually correct. You are just misinterpreting what it is showing. It shows the Net export. Not the Gross export.
Net Gauge:
Purple = supplied to the grid (positive)
0 = top centre of the gauge
Blue = supplied from the grid (negative)
Net export = gross export - gross import (values in the grid circle).
Net export: 1.8 - 5 = -3.2kWh (blue side of the gauge)