How to reproduce:
1. Open the user's attached "1235376_Repro" project
2. Observe the Console log

Expected result: No error is thrown
Actual result: System.ComponentModel.DataAnnotations.dll compatibility errors are thrown

Reproducible with: 2021.2.12f1, 2021.3.2f1
Not reproducible with: 2019.4.39f1, 2020.3.35f1, 2021.2.11f1, 2021.3.3f1, 2022.1.2f1, 2022.2.0a15

Reproduced on: macOS 12.3 (Intel)

Thrown errors:
error CS0433: The type 'ValidationResult' exists in both 'Polyfill, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' and 'System.ComponentModel.DataAnnotations, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'
error CS0738: 'EditorValidator' does not implement interface member 'IValidator.Validate()'. 'EditorValidator.Validate()' cannot implement 'IValidator.Validate()' because it does not have the matching return type of 'ValidationResult'.

Note: No compatibility issue occur when switching the "API Compatibility Level" to ".NET Framework"