It's been pointed out before, but in Try And Catch Me, Columbo assumes that Edmund and Phyllis had a bad marriage from the lack of photos of her, but of course a grieving husband could get rid of the photos during a dramatic moment (just like an ex-husband, but for other reasons), or at the very least could put them away carefully. It's a missed opportunity for Abigail that she doesn't mention that.
I have to admit, one of the few things that make Edmund look guilty to me is that quick little smirk that he gives at Abigail's photo of Phyllis, but it's not as if Columbo sees that.
I agree. The one I always found easy to explain is in Forgotten Lady and the extra time of the film running. Grace could have gone to the bathroom which would account for the extra time or have dozed off and woke up to the film having broken. She was older and it was late at night, so a jury would easily believe she fell asleep briefly while watching or had taken a bathroom break. Either would easily account for that small amount of extra time.
Going back to Forgotten Lady. Grace could claim she fixed the film immediately but stopped it to use the restroom therefore accounting for the remainder of time And it explains why the film ran longer.
Despite my affection for the episode, I admit that is a problem in that Columbo just assumes that Grace would automatically resume watching after fixing the film. Of course that I think is at heart perhaps the one great flaw of Columbo's methodology in that he so often assumes all people react a certain way and that isn't how it is with all individuals.
The bigger problem with "Forgotten Lady" is why didn't Raymond arrive earlier at the time when he should have assumed the film would be over?
Milo Janus incriminating albi in An Exercise in Fatality has always been a head scratcher for me...
I'm not sure if I'd characterize a lot of this as bad logic. I think it's more his methodology. He often says "gee that's funny", "or things don't add up." Often he's not going after airtight clues with perfect logic. Rather he's stacking up a bunch of clues that when added up point to the suspect. One example is in Death Lends a Hand when he's in the suspect's office and says that the suspect being left handed (he was ambidextrous)is a coincidence since they were just talking about a left handed murderer, and then the punchline, he says this case is just full of coincidences. He already had him pegged anyway as soon as he felt the ring on his left hand with the palm reading ruse. Again that by itself wouldn't prove anything but it leads Columbo in the right direction and to the final setup to trap the murdererer with the final piece of evidence that nails him.