We're currently experiencing link flaps on our interconnection between FFM3 and FFM5 every ~40 minutes. The darkfiber operator is aware of the situation and currently looking into the issue, as other customers (according to the provider) with darkfiber also seem to have reported an issue. We do assume a sleeve might not be fully closed, causing water entry to cause signal oscillations somewhere in Frankfurt.
Following our network architecture, we do not observe any impact to our customers.