Pre/Post Actions on buildprog not called

Trying to use pre-/post-action hooks but can't figure out what I'm missing

platformio.ini:

[env]
board = cubecell_module_plus
framework = arduino
platform = heltec-cubecell
extra_scripts = pre:${PROJECT_DIR}/scripts/extra_script.py

extra_script.py:

Import("env")

print("This will be called")

def test(source, target, env):
    print("This will never be called")

def test2(source, target, env):
    print("This will never be called")

env.AddPreAction("buildprog", test)
env.AddPostAction("buildprog", test2)

output:

extra_scripts: pre:/Users/sebastien/Documents/PlatformIO/Projects/test/scripts/extra_script.py)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------
This will be called
CONFIGURATION: https://docs.platformio.org/page/boards/heltec-cubecell/cubecell_module_plus.html
PLATFORM: Heltec CubeCell (1.1.0) > Heltec CubeCell-Module Plus (HTCC-AM02)