At the moment the negative prices are more likely due to the coal that was still running at 10% of generation even during the sunniest part of the day.

Giving inflexible generators a financial incentive to be more flexible is a good thing, as it helps clean up the grid.

Also, they've been hitting negative prices for years now. Possibly it's increased this year but that could also be an impact of efficiency improvements spurred by the way in Ukraine (generally low demand and negative prices go together).