[en] The appearance of impurity phases belonging to the quaternary oxide system SrO-GdO_1.5-CuO-RuO₂ in Ru-1212 samples is difficult to avoid. While the formation of the ferromagnetic compound SrRuO₃ may be suppressed by a precursor route involving Sr₂GdRuO₆, this latter compound shows magnetization anomalies below 30 K. We present evidence that magnetization anomalies observed for some Ru-1212 samples in this temperature range are not due to trace amounts of Sr₂GdRuO₆. Rather, the effect appears to be related to the establishment of inter-granular superconductivity and to the vortex dynamics in Ru-1212