They are both Telefónica operations; 12956 is TIWS/Telxius, 18881 is a CLEC they bought a few years ago, previously known as GVT. 
Could be a cable cut in SAM-1, the submarine fiber system operated by Telxius (the cable is also known as Emergia). 



Rubens


On Fri, Dec 21, 2018 at 6:24 PM Jared Mauch <jared@puck.nether.net> wrote:
Does anyone know what’s going on here?  There’s a lot of BGP churn coming from this network edge.

- Jared