7.0rc2 duplicate "Default" netclass when importing project from previous version

[dhaillant]

Hi,
When importing in 7.0rc2 an older project from previous versions (6.0 or 5.1), there are 2 “Default” netclasses as you can see in the screenshot below:

1. Open an old project
2. Launch PCBnew
3. In PCBnew, click on “Edit board setup including layers […]” button on top toolbar, or via menu select “File/Board Setup…”
4. Select in left pane “Design Rules/Net Classes” section.
5. In “Nectclasses” list, two “Default” rows are visible (and in “Netclass assignments”, no pattern have been automatically created)
6. If you try to validate or leave the section, a message says that “Netclass name already in use”

(Also, no pattern was created automatically as stated in topic 7.0rc eeschema - Empty Net Class list?)

Is this a bug? Thanks.
David

Application: KiCad PCB Editor x86_64 on x86_64

Version: 7.0.0-rc2-unknown-f8051d954a~164~ubuntu20.04.1, release build

Libraries:
	wxWidgets 3.2.1
	FreeType 2.10.1
	HarfBuzz 2.6.4
	FontConfig 2.13.1
	libcurl/7.68.0 OpenSSL/1.1.1f zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.2.0) libssh/0.9.3/openssl/zlib nghttp2/1.40.0 librtmp/2.3

Platform: Ubuntu 20.04.5 LTS, 64 bit, Little endian, wxGTK, xubuntu, x11

Build Info:
	Date: Jan 31 2023 20:33:57
	wxWidgets: 3.2.1 (wchar_t,wx containers) GTK+ 3.24
	Boost: 1.71.0
	OCC: 7.5.2
	Curl: 7.68.0
	ngspice: 38
	Compiler: GCC 9.4.0 with C++ ABI 1013

Build settings:
	KICAD_USE_EGL=ON
	KICAD_SPICE=ON