You have to click the SAVE
button under the channels, when changing a channel setting.
You shall not click the SAVE ALL button under the groups, because the channels inherit the group's settings.
If you set your group to GET EPG and you click the "save" button next to the group or the "save all" button under the groups, all your channels will be set to the group's setting.
It's for setting all your channels at once, without having the need to set them one by one manually.