an imaginary mischievous sprite regarded as responsible for an unexplained problem or fault, especially a mechanical or electronic one.
"a gremlin in my computer omitted a line"
No, Buffy, you're wrong again. Stop watching cartoons and do some research.
In fact, gremlin is first recorded only in the 1920s, as a Royal Air Force term for a low-ranking officer or enlisted man saddled with oppressive assignments. Said to have been invented by members of the Royal Naval Air Service in World War I, gremlin is used in works written in the 1940s for "an imaginary gnomelike creature who causes difficulties in aircraft." The word seems likely to have been influenced by goblin, but accounts of its origin are various and none are certain. One source calls in Fremlin beer bottles to explain the word; another, the Irish Gaelic word gruaimín, "ill-humored little fellow."
Gremlin was used in the 20s, agreed. But in the 40s Roald Dahl was the first to imagine the gremlin as a creature that likes to make mischief in airborne planes.
Okay, if pilots invented the term don't you think it was applied to aircraft phenomenon? It's not like the term was invented by sailors. Dahl was in the RAF and obviously learned the term there.
Dahl learned the term but was the first to apply it to an imaginary creature of his own making. Before it was a pejorative term for a low ranking officer. It says it right there in the article you quoted.
Dahl was not a cartoonist. He was an author of children's book and short stories mostly for adults. He says clearly in his autobiography, Going Solo, that he came up with the idea. Nobody has had a problem with this claim. Proof of absence.
Huh? It's just a fact that he didn't invent the term or the definition. I link my sources.
While Roald Dahl popularized the term, he did not coin it.
In the 1920's sporadic reports came filtering in from RAF pilots in Malta, the Middle East and India of 'gremlins'- mischievous sprites tinkering and causing mechanical troubles to their flying machines. At the time, it was superstition not to mention them by name.