I've now reduced watering by removing the automatic dispenser. The leaves have straightened up a bit, the burned ones obviously didn't and will not recover.
As mentioned by downwardsfromzero, potassium deficiency is a possibility. Yet I highly doubt it as I had repotted it in about 4l of (mildly) fertilized soil. Nevertheless, I'll keep feeding as normal, maybe add some banana peels and see how she'll react.
Also possibility: Cell rupture from overwatering/waterlogging. AFAIK that seems to occur rather in the inner parts of the leaves than edges. Guess only time will tell, when new growth has emerged.
Peace.