2nd and 3rd countervenoms also launch in the air so I'm not sure why they don't give enrage. Given the enrage only lasts for 7 seconds it is hard to get a lot of them anyways so I don't see why all the countervenoms shouldn't give enrage
I played around with Wetwork for a bit but wasn't able to reproduce this issue.
Since you're able to get it consistently, could you record a video of this occurring? You should be able to post here on the thread, but if not you can share a private YouTube link as well.
Shared this with the design team and they were able to break down what's likely happening in this video:
so taking a look at that video again (and to answer your question re: "is that combo applying Enrages correctly"). Starting from 0:49, which is the section in which the video creator expresses not understanding why they didn't get one of the expected Enrages, here's the sequence of events I see:
0:49 - Charge attack hit: first Enrage stack granted (because enemy changed states from a grounded state to Tripped and Val was in AlphaBlade, i.e. her charge attack state)
0:50 - Fukua lands and bounces off the ground
0:53 - Countervenom hit: second Enrage stack granted (because enemy has landed since the last stack and is now presumably transitioning into a Knockup state)
0:58 - Second CV hit: and here is where the player mentions that this "third launcher" doesn't give Enrage, but that seems expected to me since there's no indication Fukua has landed since the last one
1:04 - knockback attack which wallsplats Fukua, followed by a third CV at 1:06: this does get an Enrage which we can see at 1:08, and although we can't know for certain without being able to debug print the state transitions in-editor, I think this must have worked because the wallsplat occurred low enough to count as a landing, so she was sent into Knockup again after the hit completed
1:09 - one of the Enrages wears off (now at 2 stacks), but Laryngectomy successfully relaunches her to get a third stack again - this makes sense since we're checking for Val's SuperJump state in this case and Laryngectomy, being a launcher itself, should always grant the Enrage if you land it
So, it all seems expected to me. The "missing" third CV Enrage is (almost certainly) because she didn't get sent into a Knockup state due to not having landed since the last time she was launched.
Likely what'll happen to make this a bit more clear in game is to change some of the wording of these abilities to make it clear that opponents need to land on the ground before being launched again for these modifiers that trigger on launch to work.