Yet, on this one basic point, what they were teaching as to the time of the resurrection, Paul rightly branded them as apostates, with whom faithful Christians would not fellowship.
“Paul wrote about some in his day: “Their word will spread like gangrene. Hymenaeus and Philetus are of that number. These very men have deviated from the truth, saying that the resurrection has already occurred; and they are subverting the faith of some.” (2 Timothy 2:17, 18; see also Matthew 18:6.) There is nothing to indicate that these men did not believe in God, in the Bible, in Jesus’ sacrifice. Yet, on this one basic point, what they were teaching as to the time of the resurrection, Paul rightly branded them as apostates, with whom faithful Christians would not fellowship.” Watchtower 4/1/86, Page 31:
In their lastest history book: Jehovah’s Witnesses: Proclaimers of God’s Kingdom published in 1993, the book shows that the founder of the Watch Tower Bible and Tract Society [now the legal representatives of Jehovah’s Witnessesses] Charles Taze Russell, taught that the resurrection began in 1878:
[The Bible Students] concluded that … the resurrection to spirit life of those already sleeping in death began then.
“Based on the premise that events of the first century might find parallels in related events later, they [the early Bible Students associated with C. T. Russell] also concluded that if Jesus’ baptism and anointing in the autumn of 29 C.E. paralleled the beginning of an invisible presence in 1874, then his riding into Jerusalem as King in the spring of 33 C.E. would point to the spring of 1878 as the time when he would assume his power as heavenly King. They also thought they would be given their heavenly reward at that time. When that did not occur, they concluded that since Jesus’ anointed followers were to share with him in the Kingdom, the resurrection to spirit life of those already sleeping in death began then.” Proclaimers, Page 632
Russell taught this for the remaining years of his life. The Watchtower Society was still teaching this in 1925:
It is the understanding of the consecrated that the sleeping saints were resurrected in 1878. [Watchtower 2/1/25, Page 371]
By 1927, however, the Watchtower Society said:
… the resurrection of the sleeping saints did not take place in 1878. 
“It seems impossible to find anything in these parallel events to indicate the resurrection of the sleeping saints in 1878… Again referring to the quotation from Volume III: The conclusion there reached, that the parallels bear upon the resurrection of the saints, results from the assumption that the Lord was supposed to have taken his power and begun his reign in 1878, and that therefore he would resurrect his saints at approximately the same time. But there is nothing to indicate that Jesus Christ took his power and began his reign in 1878. He could not consistently do so until the expiration of the Gentile Times… the Gentile Times ended in 1914, and the nations were angry, and it was the Lord’s due time to take possession and oust Satan. Seeing then that the Scriptures conclusively prove that the Lord Jesus Christ did not take his great power and begin his reign in 1878, but that he did so in 1914, it follows that the resurrection of the sleeping saints did not take place in 1878.” Watchtower 5/15/27, Page 151
This presents a curious situation: Charles Taze Russell was an apostate according to the 1986 Watchtower, since he declared that the resurrection had already occurred.
Moreover, the Society says that Jehovah selected it as His earthly organization in 1918. At that time, they were still teaching Russell’s “apostate” interpretation.
Note: In the Watchtower (06/01/27), it was stated (on page 165) that the resurrection had in fact taken place in 1918: “The anointed and faithful ones constitute the temple of God… Such of course include both the sleeping saints and the faithful ones who afterwards have their instantaneous change… Jesus went to heaven to prepare a place for his saints… it would hardly seem that he would awaken the sleeping saints until this preparatory work was completed… it follows, then that the temple of God was brought together in 1918, and that that marks the time of the resurrection of the sleeping saints.”