Hello @clay shannon , Welcome to Microsoft Q&A
During the testing with blank project, I could reproduce this issue, and we suggest you send feedback with Visual Studio for this issue. And currently we have a workaround that edit the Winform platform target as x86 (not Platform dropdown), publish application package template as x86 release package.
Update
Right click winform project-> Properties-> build- >Platform.
Right the package template project -> Publish -> Create app packages-> Sideloading-> Skip package signing
Only check x86 Architecture.
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