Large-amplitude late-time radio variability in GRB 151027B

S. K., A. N. G., S. S., and D. A. K. acknowledge support by DFG grant K1 766/16-1. D. A. K. acknowledges financial support from the Spanish research project AYA 2014-58381-P, and from Juan de la Cierva Incorporacion fellowships IJCI-2015-26153 and IJCI-2014-21669. J. F. G., T. K., and P. W. acknowledge support through the Sofja Kovalevskaja award to P. Schady from the A. von Humboldt foundation of Germany. Part of the funding for GROND (both hardware and personnel) was generously granted from the Leibniz-Prize to Prof. G. Hasinger (DFG grant HA 1850/28-1).