Wow Michael, we are missing a whole lot! I'll try to post more, I would post more but I have a lot of self doubt which leads me to do a lot research but also makes me fearful over everything I say. I've listened to Zen, I think he is a Christian brother but I think he suffers the opposite problem. He seems to incorporate the conclusion he feels is true in determining whether a text is legit or not. But that is putting the cart before the horse.
Whatever this missing section is it is either before Christ, or written after Revelation which places it in the second century or later. The reason why it could be before Christ is that it contains this idea that the season would be cut short. in Luke 20:36 we can see Jesus drawing upon an understanding that we only find in Enoch. The explanation for why there will be no marriage in heaven is that we will be like the angels who do not die. The understanding of this comparison is acquired only in Enoch in the explanation of God to the angels on why he gave procreation to man. That being that the angels live eternally and man dies. So Jesus does appear to draw upon the audiences understanding of that content, which, to our knowledge only shows up in Enoch.
I would be concerned about the title "Master" in the first quote of Enoch. Because that sounds like a term we might hear in late literature for Jesus but the word in Greek is despotés (strongs 1203) and can mean Lord. In the same way that Master might have given us a late date, the use of Beloved might give us an earlier date. The only time in the new testament in which Jesus is called Beloved is when God calls Him that. No new testament writer uses "beloved" as a replacement word to indicate Jesus. The "beloved one" comes from the OT, for the Lord of Hosts (Jesus), and comes from Isaiah 5. So it seems who ever wrote this fragment is thinking from the OT perspective, before Christ. That is only half the work though, we would need an expert in all the writings of that time period to tell us if Beloved gets used as a replacement word for Jesus outside the new testament. Barring a word on that, there is at least some indication that this might be before the time of Christ.
(Since the compilation of Enoch is very large, if anyone wants an outside reference showing that this fragment is not in Enoch click the mass link below...sorry hyperlink doesn't seem to be working
https://books.google.com/books?id=kg0nAQAAIAAJ&pg=RA1-PA140&lpg=RA1-PA140&dq=book+of+enoch+For+to+this+end+the+Master+hath+cut+the+seasons+and+the+days+short,+that+His+beloved+might+hasten+and+come+to+His+inheritance.&source=bl&ots=1aFHt5zU_7&sig=uJNsdiRCW9Lh-shPbfuPCZvzJSU&hl=en&sa=X&ved=2ahUKEwiylbH1hbHfAhUOzlkKHb59BmwQ6AEwBHoECAkQAQ#v=onepage&q=book%20of%20enoch%20For%20to%20this%20end%20the%20Master%20hath%20cut%20the%20seasons%20and%20the%20days%20short%2C%20that%20His%20beloved%20might%20hasten%20and%20come%20to%20His%20inheritance.&f=false