MSB3026 warning with nested recursive paths when using Microsoft.AspNetCore.Mvc.Testing on macOS

### Description
Intermittent MSB3026 warnings occur when building test projects that reference Microsoft.AspNetCore.Mvc.Testing on macOS. The warning shows recursive nested paths and occurs approximately 40-50% of builds. The issue disappears completely when the package is removed.

### Reproduction Steps
1. Create an ASP.NET Core 10 project on macOS
2. Add test project with Microsoft.AspNetCore.Mvc.Testing package reference
3. Run `dotnet build` 10-20 times consecutively
4. Warning appears intermittently (~40-50% of builds)

### Expected behavior
No warnings on any build

### Actual behavior
Intermittent MSB3026 warning with recursive nested paths:

### Verification
Removing Microsoft.AspNetCore.Mvc.Testing package completely eliminates the warning across 20+ consecutive builds.

### Environment
- **OS:** macOS Sequoia (Apple Silicon M3)
- **Filesystem:** APFS
- **.NET SDK:** 10.0.101
- **Package:** Microsoft.AspNetCore.Mvc.Testing 10.0.1

### Additional Context
- Build succeeds despite warning
- Timing-dependent (race condition suspected)
- Adding `false` reduces frequency but doesn't eliminate
- Issue may be related to MSBuild path calculation on APFS filesystem