I know people love to get worked up from update notes before actually testing... but it's certainly possible that along with this update, SE may have also improved the drop rates of the pulse weapons. Maybe give it a couple days to see if there are reports of easier drop rates?
Even if not, there's some logic to using this as a way to recycle old content. Gives people something else to farm in hopes of a nice profit on pulse cells, and the content isn't that hard so it's accessible even to players who aren't top-end... I'm sure there are people out there willing to gamble on a rare drop that they can sell. And eventually, after the elite/gotta have it first crowd overpays for pulse stuff (to get weapons that largely won't beat the good RMEA for the people truly dedicated to a job), pulse prices will eventually drop again. In the meantime, the "newer players" can still have Kaja weapons as a solid option from obtained by just doing some Ambuscade.
I've turned in thousands of keys, not a single pulse weapon from them. The pool is too big. Random is random.
I'm pretty sure S-E makes regular adjustments to SP dial/key drops to favor certain items in certain months. Lots of people noticed significantly higher Dynamis [D] shard/void armor item rate from dial for a while shortly after Divergence began. I certainly did, during one of the SP key months I was averaging a couple shard/void pieces per day on 18 characters (main + 15 mules, plus my alt & 1 mule), probably something in the neighborhood of a 5% rate. After a future update, that rate dried right up...
I've seen other months with noticeable themed items showing up with more regularity. Like one month I kept getting Sealed Container NM basket pop items, but that was the only month I've seen those happen with such frequency. Here's hoping this month has a higher chance of pulse stuff.
Any yeah, the shinies are also part of AMAN Trove loud thud pool. I've seen two Annealed Lances that way since Trove started.