Pamac updates an AUR package version (in the list of apps and in the detailed description) only after installation
but before installation I did Menu -> Refresh databases
but looks like AUR info cached somewhere else where pamac connects to.
pacman -Qi pamac
Name : pamac-gtk
Version : 10.2.0beta-1
...
Operating System: Manjaro Linux
KDE Plasma Version: 5.22.4
KDE Frameworks Version: 5.85.0
Qt Version: 5.15.2
Kernel Version: 5.14.0-1-MANJARO (64-bit)
Graphics Platform: X11
Installation was done recently with the manjaro-kde-21.1-stable-staging-210816-linux513.iso
image (https://github.com/manjaro/release-review/releases/tag/202108162144)
and then got all updates by that time.
Thanks!