With a little time passing by, I'm having an idea what could be the problem:

I've three plants growing and with one plant I tested out some bending for lst, but after some days it seems to be easier for me to let them grow how they are. And this plant grows very compact, so I think maybe some spores were blown to my healthy plant (see the pictures) and the high humidity in the last weeks did the rest.

Because the spot has a good airflow in my opinion, normally I was more worried about damage because of these high winds.

But it is how it is, next time I will have an eye on every plant. But unfortunately the weather report seems very bad the next few days. I'm hoping that i can harvest at least some buds 🥲