As i posted here the webinterface use the user client browser time instead of local configured time from Pi.
My webinterface hide then querys from last hour because i use the gHacks user.js which use "privacy.resistFingerprinting" to increase the privacy while browsing. But this setting set UTC to UTC 0.
Cause i live in UTC 1 (and configured this in Pi configs), PiHole webinterface hide now the querys between this two UTC times.
So please use local time, or give the user a option to configure which time should be used instead of just read the browser client time.