Multiple SetEnvrionmentVariable override each other when launching multiple nodes

Bug report

Required Info:

• Operating System:
  • Ubuntu 20.04
• Installation type:
  • Binaries
• Version:
  • Galactic
• DDS implementation:
  • Cyclone DDS

Steps to reproduce issue

Generate multiple nodes and call SetEnvironmentVariable in the LaunchDescription:

from launch import LaunchDescription
from launch_ros.actions import Node
from launch.actions import SetEnvironmentVariable


def generate_launch_description():
    return LaunchDescription([
        SetEnvironmentVariable(name='TEST', value='0'),
        Node(
            package="test_0",
            executable="test_0",
            name="test_0_node",
            output="screen",
        )
    ])

from launch import LaunchDescription
from launch_ros.actions import Node
from launch.actions import SetEnvironmentVariable


def generate_launch_description():
    return LaunchDescription([
        SetEnvironmentVariable(name='TEST', value='1),
        Node(
            package="test_1",
            executable="test_1",
            name="test_1_node",
            output="screen",
        )
    ])

Launch both nodes:

from ament_index_python.packages import get_package_share_directory

def generate_launch_description():

    nodes = ["test_0", "test_1"]
    includes = []

    for n in nodes:
        includes.append(launch.actions.IncludeLaunchDescription(launch.launch_description_sources.PythonLaunchDescriptionSource(get_package_share_directory(n) + '/launch/' + n + '_launch.py')))

    return launch.LaunchDescription(includes)

Expected behavior

When accessing the environmental variable in node 'test_0' it should have the value '0'.
When accessing the environmental variable in node 'test_1' it should have the value '1'.

Actual behavior

When accessing the environmental variable in node 'test_0' it has the value '1'.
When accessing the environmental variable in node 'test_1' it has the value '1'.

Additional information

Start by reproducing the issue with the two Python launch descriptions using SetEnvironmentVariable and IncludeLaunchDescription, then inspect the corresponding launch package entry points. Done means each included node observes its own TEST value rather than the value from the last launch description.