It really depends on the size and placement of the oversupply, this could cause localized grid overloading.

"However, BDEW warned that around half of the new capacity came in the form of small-scale systems under 100 kilowatt each, which under current rules feed into the grid whatever they produce, without the option to curtail production when this is necessary to ensure grid stability."

https://www.cleanenergywire.org/news/germany-adds-record-175...

Smart electric meters for individual PV producers that signal and account for negative prices would help. e.g. if your balcony solar power pushes electricity during oversupply you pay penalty.