大毘盧遮那成佛經疏 2.15

2.15

經云「社怛梵」者，謂與知者外道宗計大同，但部黨別異，故特出之耳。

The sūtra says: "Jantvā." This means that its doctrine largely agrees with the non-Buddhist views of the knower, but because it belongs to a distinct sectarian division, it is specially singled out.