This means that it had 2 votes to be payed at block 526268 but the winner was the other node. This happens sometimes because we have low threshold on votes for masternode to be counted as paid to help consensus because in 0.12.0.x we had no easy (cpu/hdd wise) way to confirm which node was actually paid or if any node was paid at all. We are working to make this much more robust and yet not too cpu/hdd heavy in 0.12.1.x (hopefully).

Other than that you node is ok imo, keep it running and it should get paid soon.

PS. My node missed a payment few days ago too...