This happens with so many editors/publications and people are either subsumed or rejected. Grammarly is a robotic joke and does not understand English. People who rely on it are making a terrible mistake, especially if they use it as a cause for rejecting otherwise good work from hard-working writers. You are one of many to point this out and, by drawing so much attention to the subject, you are to be commended. Unfortunately, as noted in these comments, Grammarly still commands the day. While succesful writers' work is still questioned and rejected by editors who do not know what they are about.