Why is this code not working to generate planetary modifiers?

[Walkaboutout]

This worked back in 3.4.x and before that. It no longer works in 3.11. No modifiers are added to these planets when they generate in-game. Do I need to do this differently now, or did something get broken?

    planet = {
        count = 1
        orbit_distance = 25
        class = "pc_continental"
        orbit_angle = { min = 90 max = 270 }
        size = 25
        init_effect = {
            add_modifier = { modifier = strong_magnetic_field }
            add_modifier = { modifier = hazardous_weather }
            add_deposit = d_betharian_deposit
            add_deposit = d_betharian_deposit
            add_deposit = d_geothermal_vent
            create_archaeological_site = it_was_aliens_site
        }
    }

    planet = {
        count = 1
        orbit_distance = 25
        class = "pc_ocean"
        modifiers = none
        orbit_angle = { min = 90 max = 270 }
        size = 25
        init_effect = {
            add_modifier = { modifier = lush_planet }
            add_modifier = { modifier = titanic_life }
            create_archaeological_site = site_fossilized_jellyfish
        }
    }