fstrim.timer always triggers at 00:00, use RandomizedDelaySec

fstrim.timer always triggers at 00:00:

$ systemctl list-timers fstrim.timer
NEXT LEFT LAST PASSED UNIT ACTIVATES
Mon 2019-06-24 00:00:00 CEST 3 days left Mon 2019-06-17 00:00:06 CEST 3 days ago fstrim.timer fstrim.service

1 timers listed.
Pass --all to see loaded but inactive timers, too.

This can be an issue if concurrent runs cause increased I/O load on multiple servers which are part of the same system architecture (I have no hard facts via monitoring on this, but assume this can be an issue).

/lib/systemd/system/fstrim.timer does not try to randomize the start time.
systemd.timer(5) suggests that RandomizedDelaySec can be used to introduce variable start times, allowing for balancing out the (suspected increased) I/O load across multiple systems.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: util-linux 2.31.1-0.4ubuntu3.3
ProcVersionSignature: Ubuntu 5.0.0-17.18~18.04.1-generic 5.0.8
Uname: Linux 5.0.0-17-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.6
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Jun 20 19:52:17 2019
SourcePackage: util-linux
UpgradeStatus: No upgrade log present (probably fresh install)