Ananicy version: yesterday's git.
Log

Conf file
## Ananicy 2.X configuration
# Ananicy run full system scan every "check_freq" seconds
# supported values 0.01..86400
# values which have sense: 1..60
check_freq=5
# Verbose msg: true/false
cgroup_load=false
type_load=false
rule_load=false
apply_nice=false
apply_ioclass=false
apply_ionice=false
apply_sched=false
apply_oom_score_adj=false
apply_cgroup=false
check_disks_schedulers=true
My system
OS: Linux Mint 20.2 x86_64
Host: 20KH001UKP ThinkPad X1 Carbon 6th
Kernel: 5.4.0-81-generic
Uptime: 8 days, 14 hours, 4 mins
Packages: 3337 (dpkg), 8 (flatpak)
Shell: bash 5.0.17
Resolution: 2560x1440 @ 60.01Hz
DE: Cinnamon 5.0.5
WM: Mutter (Muffin)
WM Theme: Mint-Y-Dark (Mint-Y-Dark)
Theme: Mint-Y-Dark [GTK2/3]
Icons: Paper [GTK2/3]
Terminal: xfce4-terminal
Terminal Font: InconsolataGo 12
CPU: Intel i7-8550U (8) @ 1.800GHz
GPU: Intel UHD Graphics 620
Memory: 4319MiB / 15903MiB
Disk (/dev/nvme0n1p4): 17G / 40G (46%)
Disk (/dev/nvme0n1p2): 166G / 405G (44%)
Disk (udev): 0 / 7.8G (0%)
Further information
It seems - but I have not had long to test this - that restarting the service solved both problems, those problems being (1) the excessive logging, (2) the erroneous logging. Perhaps I had managed somehow to misconfigure ananicy?