There's always something. Did you know that nuclear-power producing France comes close to crashing the grid basically every other winter? See eg https://www.cre.fr/Actualites/RTE-fait-appel-aux-industriels... for the announcement from 2019, but I remember reading articles about this at least as early as 2012.
This is because a lot of French households use electrical heating (because it was encouraged by the government to use the huge sovereign electrical capacity), so cold put a huge stress on the grid. This is not related to nuclear power per se.
It's not entirely unrelated: Nuclear plants make bad peakers, and I suspect the older plants probably also aren't too good at load-following. The French also not only get into trouble when demand is high in winter, but also when it's too hot ín the summer because they don't want to boil their rivers...
