"Error applying transforms" when installing multiple instance MSI - wix

Question

I'm trying to explore instance transforms with WiX version 3.7.1224.0. I created a test project (source below) and I can install the default ProductCode propertly, but when I try to install the resulting MSI, I get an error:
msiexec /i SetupProject1.msi /l*vx install.log MSINEWINSTANCE=1 TRANSFORMS=":Alpha"
Error applying transforms. Verify that the specified transform paths are valid
The install.log seems to suggest there's a row in the Property table that the "regular transform" is expecting to find and modify, but I'm not sure what property it might be looking for. I've been reading the MSDN documentation on multiple instance transforms as well as the WiX documentation and blog posts describing how <InstanceTransforms> works, but I'm at a loss for what it's looking for.
Compilation
"%WIX%\bin\candle.exe" -out obj\Debug\ -arch x86 Product.wxs
"%WIX%\bin\Light.exe" -out SetupProject1.msi -cultures:null obj\Debug\Product.wixobj
Product.wxs
<?xml version="1.0" encoding="UTF-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
<Product Id="*" Name="SetupProject1" Language="1033" Version="1.0.0.0"
Manufacturer="ABC"
UpgradeCode="ce6fdce7-5c23-4379-af59-f70c520ad1b6">
<Package InstallerVersion="500" Compressed="yes" InstallScope="perMachine" />
<MajorUpgrade DowngradeErrorMessage="A newer version of [ProductName] is already installed." />
<MediaTemplate EmbedCab="yes" />
<Property Id="INSTANCENAME" Secure="yes" />
<InstanceTransforms Property="INSTANCENAME">
<Instance Id="Alpha" ProductCode="{16756BA2-9FAC-4BA4-9FFD-FC2F06B1315E}" ProductName="SetupProject1 Alpha"/>
<Instance Id="Bravo" ProductCode="{D32D3643-5A46-421E-9216-1B1C9037DC37}" ProductName="SetupProject1 Bravo"/>
<Instance Id="Charlie" ProductCode="{ED9BC4F0-8CB8-4813-B677-F0E4A52D1890}" ProductName="SetupProject1 Charlie"/>
</InstanceTransforms>
<Feature Id="ProductFeature" Title="SetupProject1" Level="1">
<ComponentRef Id="FileComponent" />
</Feature>
<Directory Id="TARGETDIR" Name="SourceDir">
<Directory Id="ProgramFilesFolder">
<Directory Id="INSTALLFOLDER" Name="SetupProject1">
<Component Id="FileComponent" Guid="*">
<File Source="File1.txt" KeyPath="yes" />
</Component>
</Directory>
</Directory>
</Directory>
</Product>
</Wix>
install.log excerpt
MSI (c) (E4:8C) [13:49:28:343]: TRANSFORM: Applying regular transform to database.
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: _Tables 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: _Columns 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: _Validation 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: AdminExecuteSequence 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: AdminUISequence 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: AdvtExecuteSequence 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: Component 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: Directory 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: Feature 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: FeatureComponents 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: File 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: InstallExecuteSequence 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: InstallUISequence 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: LaunchCondition 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2262 2: Media 3: -2147287038
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 2254 2: 3: Property
DEBUG: Error 2254: Database: Transform: Cannot update row that doesn't exist. Table: Property
1: 2254 2: 3: Property
Error applying transforms. Verify that the specified transform paths are valid.
Alpha
MSI (c) (E4:8C) [13:49:28:343]: Note: 1: 1708
MSI (c) (E4:8C) [13:49:28:344]: Product: SetupProject1 Alpha -- Installation failed.
MSI (c) (E4:8C) [13:49:28:344]: Windows Installer installed the product. Product Name: SetupProject1 Alpha. Product Version: 1.0.0.0. Product Language: 1033. Manufacturer: ABC. Installation success or error status: 1624.

Answer 1

It turns out the transform is setting the INSTANCENAME property (obvious, in retrospect). The property needs to have a default value so it's listed in the Property table.
<Property Id="INSTANCENAME" Value="Default" />