Yup, it looks like this is just a vanilla RPG maker problem. It happens if I keep opening the DevTools while refreshing, but I haven't seen it yet without opening the dev window. Strange bug. I thought it went away after I commented your code because, by coincidence, I must also have not had the dev window open when I tested at that time. Hope they fix it in future as it will make debugging somewhat frustrating at times. Maybe I should just go deeper myself and include an override of the method in question in my own code, if I can get around it that way. Thanks for your help!