VX mapping nightmare!, Ghost tiles? Options

[Lato]

Ok I dont have much experience in VX, mostly because it sucks, it sucked on day one, and was replaced by ace cause it sucks BUT I have a question. I have a map I was editing, it was a forest filled town with a lot of trees, the ONLY thing I did was take out like 1/3 of the trees, now when I walk through the town I run into invisible walls here and there, I looked at the mapping to see I maybe I made something a impassable tile but no, its just normal grass to, I have no idea if this has something to do with me taking away the trees or what. has this happened to anyone else?