Mr. Monk and the Actor - S5-E1
Corrected entry: Monk tells David about Trudy's murder, saying she told him that day she was going out to run an errand for his brother Ambrose. But this contradicts the facts established in "Mr. Monk & the 3 Pies," where Monk didn't know why Trudy had gone out that day until Ambrose told him. That's definitely not a fact that Monk would get wrong.
Correction: Well for one thing Trudy was supposed to be doing an errand for Ambrose that day however, as stated in previous episodes the errand was never specified and Monk did not understand what she was doing in the parking lot most likely because the errand had nothing to do with where she was. And, If I recall correctly even stated that she was supposed to be doing him an errand but ended up in the parking lot maybe waiting for someone. So monk in fact did not know what she was doing there.
Correction: Given that Monk "found out" several times that Kelly street was not an address one must assume that his memory is not very reliable when it comes to Trudy's murder and everything surrounding it.