[andreasdz]

Without really understanding much what is going on, this seems to be related:

"System split registered in the synchronous area of Continental Europe – Incident now resolved"

https://www.entsoe.eu/news/2021/01/08/system-split-registere...

[smartbit]

From https://www.electricitymap.org/zone/RO it seems there was a drop in hydropower ~1GW around that time in Romania.

[xenonite]

commentary in German: https://www.saurugg.net/2021/blog/stromversorgung/bedenklich...