This question requires some clarification in that there were (and still are) those who denied a resurrection of/in the flesh/body, while perhaps still admitting to a resurrection of something. This argument resurfaced about CE 200. Tertullian deals with it in many places against teachings sourced some 50 years earlier to Marcion, Vallentinus, and others.
Those heretical teachings (no resurrection of the flesh) arose for various reasons having to do with answering the question about the nature of who Christ Jesus is and thus the type of resurrection (flesh or otherwise).
They who are so anxious to shake that belief in the resurrection which was firmly settled before the appearance of our modern Sadducees, as even to deny that the expectation thereof has any relation whatever to the flesh, have great cause for besetting the flesh of Christ also with doubtful questions, as if it either had no existence at all, or possessed a nature altogether different from human flesh. For they cannot but be apprehensive that, if it be once determined that Christ’s flesh was human, a presumption would immediately arise in opposition to them, that that flesh must by all means rise again, which has already risen in Christ. Therefore we shall have to guard our belief in the resurrection from the same armoury, whence they get their weapons of destruction.
As well, there's this.
Thus, then, you have the Lord affirming against the Jewish heretics what is now encountering the denial of the Christian Sadducees—the resurrection of the entire man.
So, at least one answer to the OP question about denying the (flesh) resurrection is it sources very early in Christian history to those who denied that Jesus is the Christ, Son of the Living God.
PS. Although not asking for it, in turn the source of that teaching (resurrection of something, but not of the flesh) relates to the teaching about the nature of the birth of Christ. Those in the church, like Marcion and others, believed in the virgin conception, but denied a natural human birth, unlike Tertulllian. From that as noted, they believed in some resurrection, but not to one of "evil" flesh.