What common mistake do developers make with Guards, why does the mistake cause problems, and what is the safer approach?

What common mistake do developers make with Guards, why does the mistake cause problems, and what is the safer approach? One recurring problem with guards is applying it without understanding the boundary it protects. Logging a user in successfully but failing to regenerate the session identifier as part of a secure session-authentication workflow. In addition, Guards define how authentication is performed for a particular request context. Safer engineering approach: keep the responsibility in the correct layer, use the framework's supported API, validate and authorize inputs, avoid hidden side effects, and verify the behavior with tests.