I had a leak on one of the same windows you are describing. It was on a bedroom window where the emergency exit was on one side and a vent was on the other. For some reason the gasket or window shifted and the vertical seal was not hitting the window. I shifted it back and all is good now. It seems like water filled the inside track and was easy to detect the source of the leak. It would be easy enough to tape off the window to the trailer with some wide vinyl tape to help determine the source of the leak.
I had one window where the metal strip that holds the opening mechanism came loose from the glass. It appeared to have been mounted with double sided tape. I cleaned the surfaces with solvent and glued it back with Gorilla Glue and held it in place with spring clamps while drying. Good as new.