ls -lh /var/log/pihole-FTL.log
-rw-r--r-- 1 pihole pihole 13K Mar 16 08:52 /var/log/pihole-FTL.log
so this is correct
about pihole -f (= really logrotate)
I think both You and I forgot about this
Witch implies pihole -f doesn't do anything (if logrotate is available) unless it's really a new day.
There is a pihole.log.1 today, but there wasn't yesterday, despite all the pihole -f commands.
The pihole-FTL error remains, although everything seems to be working...