Looking at the dump from the service, plus the dbus log, the tenth parameter of the libsession.so entry is "false", which is this part of the code is responsible for:
is_image is definitely a valid pointer as otherwise we wouldn't get the image data nor would the 9th param (sensitive) be true. So, it seems like the indicator is setting it's entry's GtkImage to visible = FALSE.
Looking at the dump from the service, plus the dbus log, the tenth parameter of the libsession.so entry is "false", which is this part of the code is responsible for:
is_image ? gtk_widget_ get_visible (GTK_WIDGET (entry->image)) : FALSE
is_image is definitely a valid pointer as otherwise we wouldn't get the image data nor would the 9th param (sensitive) be true. So, it seems like the indicator is setting it's entry's GtkImage to visible = FALSE.