What about when a thoroughly proven falsehood becomes a 'modified truth', then returns to being a thoroughly proven falsehood? Was it ever 'truth' at all?
What you call a murmuring phase I would call waking up to the fact that certain teachings are no longer credible.
And to correct your current understanding and align it with the latest 'modified truth', Jude 8 is not talking about the GB, it is talking about elders.
It's understandable why you got this wrong however:
WHO ARE THE 'GLORIOUS ONES'?
All anointed - w60 9/1 p. 539 par. 14 Awake Worshipers in the Time of the End
The “glorious ones” here referred to are not any who are bright and shining in their own eyes or who are glorious in the eyes of others due to their personal achievements. Those who are the brothers of the King Jesus Christ have been selected as heirs of the heavenly kingdom—a glorious privilege indeed!
All anointed - w65 10/1 p. 592 par. 7 Execution of Divine Judgment upon the Ungodly
Who are these “glorious ones”? They must be those who receive glory from Jehovah God and his Lord of lords, Jesus Christ. According to Isaiah 60:1, 2, Jehovah’s “own glory” would be conferred upon the remnant of spiritual Israel, the anointed Christians.
Elders - w79 1/15 p. 25 Why Keep Free from Murmuring?
They were individuals who were “disregarding lordship and speaking abusively of glorious ones,” or responsible men in the congregation.
Elders - w80 1/15 p. 19 par. 10 Are You a Loyal Subject of God’s Government?
Further describing them, the apostle says: “Daring, self-willed, they do not tremble at glorious ones [persons entrusted with oversight within God’s congregation] but speak abusively.”
Anointed elders - w82 8/15 p. 28 pars. 14-15 Heed the ‘Warnings Placed Before Us’!
Those ungodly persons also spoke abusively of “glorious ones” (literally, “of glories”), evidently those who had certain glory conferred upon them by Jehovah God and Jesus Christ... 15 Certainly, those of Christ’s anointed followers who serve faithfully as appointed Christian overseers have had glory, or honor, conferred upon them.
Anointed elders - w89 9/15 p. 22 par. 8 Be Obedient to Those Taking the Lead
Surely, we do not want to be like the “ungodly men” of Jude’s day who ‘disregarded lordship and spoke abusively of glorious ones,’ anointed Christian elders with God-given glory, or honor, conferred upon them.
Anointed elders - w91 4/15 p. 31 Beware of Apostates!
Unlike the archangel Michael, who would not even bring a judgment against the Devil in abusive terms, the ungodly men spoke abusively of “glorious ones,” evidently those with certain glory conferred upon them by God and Christ as anointed elders.
Elders - w97 9/1 pp. 15-16 pars. 13-14 Beware of False Teachers!
Jude writes that “these men, . . . indulging in dreams, are defiling the flesh . . . and speaking abusively of glorious ones.” (2 Peter 2:10; Jude 8) In what sense, though, do they “look down on lordship” and speak “abusively of glorious ones”? 14 They do so in that they despise divinely constituted authority. Christian elders represent the glorious Jehovah God and his Son and, as a result, have certain glory conferred upon them. True, they make mistakes, as did Peter himself, but the Scriptures urge members of the congregation to be submissive to such glorious ones.
Elders - w98 6/1 p. 17 par. 10 “Put Up a Hard Fight for the Faith”!
But if we dwell on their faults and undermine respect for them, might we be “speaking abusively of glorious ones”? In verse 10, Jude mentions those who “are speaking abusively of all the things they really do not know.” Some will, at times, criticize a decision made by a body of elders or a judicial committee.
Elders - w08 11/15 p. 22 par. 9 Highlights From the Letters of James and of Peter
While “glorious ones,” that is, Christian elders, have faults and may err at times, we must not speak abusively of them.
Splash