FilmConvert has released a beta v3.07 version of the FilmConvert Nitrate for Final Cut Pro plugin to address an issue when working with the latest version of Final Cut Pro, 10.5.3.
⁃ UI window is not currently resizable
⁃ Multiple UI windows can be opened, but only the newest window will function – recommend only opening a single instance of the UI controls
⁃ projects saved this 3.07 version of the plugin will not function with earlier versions of FilmConvert Nitrate
According to FilmConvert, they are currently working with Apple to fix the remaining compatibility issues, and they will release a new version once those problems have been sorted out.
The beta v3.07 version of the FilmConvert Nitrate for Final Cut Pro plugin installer is available here: https://filmconvertoz.s3.ap-southeast-2.amazonaws.com/FC+Nitrate/Notarized/FilmConvertNitrate.FCPX-3.07.dmg