Outlander Season 5 made a slight change to the Graham Menzies storyline. There's a very good reason for this and it really doesn't matter!
In Outlander Season 5, Episode 5, we got a story from "Voyager." As Claire treated the Beardsley twins and removed their tonsils, Claire thought back to a time a patient died of a penicillin allergy. Graham Menzies's storyline did experience a small change, but there's a very good reason for this.
In fact, I don't think the change to the story even disrupted anything. It didn't ruin anything unless you really want the entire book to be told the exact same way on the screen. And let's face it; it was never going to be possible from the very first day to tell the story exactly.
In the end, the story involving Graham Menzies in Outlander Season 5 brought us to the same point as it did in "Voyager." It was never about the patient but about what the patient encouraged Claire to do. It was all about Claire deciding to head back to the UK, where she would find out the truth about Jamie.
Changing Graham Menzies's storyline from the "Voyager" one was a necessity. In the novel, it turns out that he dies of cancer, something that Claire doesn't catch. She's forced to take time off because of it rather than choosing to take that time off. In the series, her patient tested negative for a penicillin allergy but it was a false negative. This was a death that hit Claire hard.
Due to the time in an episode, it was only natural that the storyline would be adapted slightly. Plus, in a TV show, it's got to connect to the main story taking place. The use of a flashback has to make sense within the episode, and connecting it to penicillin did just that. Claire thought about the dangers of penicillin and the fact that the tests aren't always conclusive or right. We got a connection to her worries about the Beardsley twins having the allergy.
The show creators have a big job transforming the books. They need to adapt the storylines to fit the method of storytelling and the time they have available. This is one of those cases.
The important part of the episode was included: explaining that he was the reason Claire got back to Jamie.
Outlander Season 5 continues on Sundays on STARZ. Watch Outlander with a FREE 7-day trial of Amazon Channels!