A month…? Mmmmm, experience usually is approximately a few minutes between both. 
Interestingly, on my Manjaro machine and it doesn’t recognise the ls -id /var/log/installer command.
[xxxxx@xxxx ~]$ uptime
11:40:48 up 1:12, 1 user, load average: 0.90, 0.84, 0.83[xxxx@xxxx ~]$ ls -ld /var/log/installer
ls: cannot access ‘/var/log/installer’: No such file or directory[xxxx@xxxx -7470 ~]$ ls -ld /lost+found
drwx------ 2 root root 16384 Oct 11 15:01 /lost+found[xxxx@xxxx ~]$
To quote the Debian wiki (from memory) when diagnosing OS or hardware issues, there could be a multitude of reasons, but do not dismiss solar flares, that could cause such anomalies.
