What is the difference between a police officer's testimony that the agents had probable cause to search and arrest Moses?

The majority is apparently willing to accept the officer's statement that she thought the agents had probable cause to obtain a warrant to search Moses. Majority op. at 285. But the majority is unwilling to credit the same officer's testimony that she did not believe there was probable cause to arrest Moses. This paradoxical position is even more perplexing given the majority's acceptance of police officers' expertise in evaluating suspicious conduct: " 'it is important to recall that a trained law enforcement agent may be able to perceive and articulate meaning in a given conduct which would be wholly innocent to the untrained observer.' " Id. at 284 (quoting United States v. Mendenhall, 446 U.S. 544, 563, 100 S.Ct. 1870, 1882, 64 L.Ed.2d 497 (1980) (Powell, J., concurring)).