Copy paste within Footprint Editor not saving

Description

When copying features from one footprint to another inside the Footprint Editor, changes are not actually saved.

Steps to reproduce

1. Open a footprint in Footprint Editor
2. Copy some features to clipboard (line segments, text, pads, etc)
3. Open another footprint
4. Paste contents of clipboard (this step works as expected)
5. Save the footprint
6. Close, and re-open the footprint you pasted into
7. Notice that the features you pasted are missing

KiCad Version

Application: KiCad Symbol Editor x64 on x64

Version: 8.0.0-rc2, release build

Libraries:
	wxWidgets 3.2.4
	FreeType 2.12.1
	HarfBuzz 8.3.0
	FontConfig 2.14.2
	libcurl/8.5.0-DEV Schannel zlib/1.3

Platform: Windows 11 (build 22631), 64-bit edition, 64 bit, Little endian, wxMSW

Build Info:
	Date: Jan 21 2024 19:32:51
	wxWidgets: 3.2.4 (wchar_t,wx containers)
	Boost: 1.83.0
	OCC: 7.7.1
	Curl: 8.5.0-DEV
	ngspice: 42
	Compiler: Visual C++ 1936 without C++ ABI

Build settings: