Alpha shadow not working ??

[osmose]

hi,

i've switched from 1.10 to 1.13 but it is the same.
I have a room with a side made from glass and structure to hold it. I sould have the shadow structure on the floor if light ( daylight or hdri ) placed correctly but nothing happened. if i remove the glass object things are ok and light enter the room and shadow are on the floor.
Direct light and alphashadow on.

thanks for the help.

[edit]
ok i've found i have to check fake shadows in material editor.
hope it is the correct behavior ??