So far I remember trims do not run under a driver but anyway the fstrim service just runs the fstrim command itself triggered by a timer, I just don't know if: pacman packages can enable services at all and since I do not know also absolutely nothing about systemd strange practices rather than removing a symlink and remove exec privileges, like I was used to in the past so I'm a bit clueless on that...
The package looks identical to the ubuntu one so I think it's enabled by default, but what if someone upgrades that package when you have previously disabled that service? If it just re-enables itself that would be problematic in this case, apt acknowledges that (I was almost sure about it) but pacman is rather plain and simple
Btw it was not a coincidence also because the "mistake" was taken by a red hat employee himself which was also the maintainer itself, so pretty reasonable...
Also, I'm not a programmer so I don't like criticizer other people work, but I can't really tell how something like that could even happen? That could be the worst case scenario
Back to another story, since manjaro let's you easily create an lvm encrypted installs but also have a slightly different release cycles, this could be both a nightmare and a benefit as they update kernel a bit later there, so some people could be saved here
Also yes, the specific issue happens only when you use a specific function on a specific kernel version, but it's still one of the main linux kernel modules and not a simple driver for a device
I'm also sure Gentoo uses pretty old kernel releases by default, as for fedora who knows? I'm just sure Ubuntu 19.04 is on 5.0
EDIT: yeah by default it uses 4.19 without masks
but anyway something I noticed is every distro has its own concept of stability