Diary of a Perfect Murder - S1-E1
Character mistake: Prosecutor "Death Row" Hawkins finishes speaking with prospective jury member Mr. Cooper and tags in The Defense attorney, saying, "Mr. Matlock, your witness." Naturally, Cooper is not a witness of anything; they are selecting the jury.
The Scandal - S9-E2
Character mistake: Billy has second thoughts about selling his late sister's beach house to a developer who plans to tear it down and build a hotel. Billy tells Ben, "She lived the last years of her life here." But in part 1 of this two-part episode, it was established that the woman had lived in the house for only six months.
The Singer - S7-E5
Character mistake: Near the end, Matlock says that he can prove who killed KC. The burden of proof lies with the prosecution; as a defense attorney, Matlock doesn't have to prove anything.
Answer: If it was ever found out that she was at Terry's house before he was killed, there's a possibility that a lot of people would have begun to suspect her of murdering Terry. By claiming that she wasn't, she was hoping that people wouldn't accuse her of the murder.