Not sure if anyone has had this on release of Season of the Splicer but prior to launch I had spent a considerable amount of time grinding the oh so boring Symmetry catalyst and was around halfway to completion. Noticing team Scorch activity was available and knowing this would speed up progress with the short match times, I spent 2 hours grinding matches, then checked my Symmetry for progress only to find the Catalyst had been removed from my weapon and all the progress I had made. Bit of an explanation would be great please Bungie.
Sounds like you're referring to the quest for the catalyst, not the catalyst itself, as the catalyst does not require any activity completions.
If so, it should be in you quest inventory, not the weapon. Is it not there? Have you checked the Quest Archive in the Tower (it's to the left of the Postmaster)?