platform_packages throws a Python TypeError when compiling

[theelims]

Configuration

Operating system: Windows 10 64bit

PlatformIO Version (platformio --version): Core 4.2.1 Home 3.1.1

Description of problem

I needed to test some pull request for the Arduino Nano 33 BLE Core and tried to use the platform_packages command in platformio.ini. The repository downloaded well, but when compiling I get a Python TypeError.

Steps to Reproduce

1. Change plaformio.ini and include github
2. Build blink

If problems with PlatformIO Build System:

The content of platformio.ini:

[env]
platform = nordicnrf52
board = nano33ble
framework = arduino
build_type = release
monitor_speed = 115200

[env:elims_nano33ble]
platform = nordicnrf52
platform_packages = 
    ; use upstream Git version
    framework-arduino-nrf52-mbedos @ https://github.com/theelims/ArduinoCore-nRF528x-mbedos.git

Output:

Processing elims_nano33ble (platform: nordicnrf52; board: nano33ble; framework: arduino)
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Verbose mode can be enabled via `-v, --verbose` option
CONFIGURATION: https://docs.platformio.org/page/boards/nordicnrf52/nano33ble.html
PLATFORM: Nordic nRF52 4.1.0 > Arduino Nano 33 BLE
HARDWARE: NRF52840 64MHz, 256KB RAM, 960KB Flash
DEBUG: Current (cmsis-dap) External (cmsis-dap, jlink)
PACKAGES:
 - framework-arduino-nrf52-mbedos d76ca56
 - tool-sreccat 1.164.0 (1.64)
 - toolchain-gccarmnoneeabi 1.80201.190214 (8.2.1)
LDF: Library Dependency Finder -> http://bit.ly/configure-pio-ldf
LDF Modes: Finder ~ chain, Compatibility ~ soft
Found 6 compatible libraries
Scanning dependencies...
Dependency Graph
|-- <ADS1X15> 1.3.0
|   |-- <Wire>
Building in release mode
*** [.pio\build\elims_nano33ble\src\main.cpp.o] UserError `TypeError `File C:\users\elims\.platformio\packages\framework-arduino-nrf52-mbedos@src-ef65cf1c0d158c1f05269a58b97dfa62\cores\arduino\api found where directory expected.' trying to evaluate `${_concat(INCPREFIX, CPPPATH, INCSUFFIX, __env__, RDirs, TARGET, SOURCE)}'' trying to evaluate `${_long_incflags_hook(__env__, _CPPINCFLAGS)}'
===================================================================================================================== [FAILED] Took 2.11 seconds =====================================================================================================================