But what's happening with the game when my Melee charge gets used, and is put on CD (the game obviously realised I melee'd someone),but the Enemy doesn't take any damage. Not even a post mortem. At what point could SLR, or a declining player base have to do with melee damage repeatedly getting lost in the ether? I obviously hit something on my end, if the melee charge gets consumed.

If there is a declining player base, or more likely more people playing SRL than the other crucible play lists, the matchmaking will have trouble connecting groups of people who have good connections with each other, because there are less players to choose from in queue. I'm more likely to get thrown into a more globally diverse group. And being in a match with people from Europe and Australia and the U.S. and Canada etc. all at once strains the system

I was just thinking they -blam!-ed something up on the back end coding/programming of the PvP stuff that might be causing unusual latency, bugs, glitches, ect... SRL is new and maybe it's implementation had unintended consequences elsewhere. Basically I was agreeing with your OP and speculating an explanation as to why the crucible feels off right now.