I was getting the same issue in 4.19.0. The trick of renaming the struct variable, then immediately (no compile needed) renaming it back to what is was, then recompiling the blueprint did the trick! Well, then after doing it all, I exited and reopened the editor. And for good measure, fixed up redirectors. The last two sometimes fixing problems (warning—the very last, fixing up redirectors, has broken things for me in the past! esp. materials calling material functions that moved)