I have discovered that you don't have to mess with the exports file, just hit F12 on your browser (developer mode) and change the maxlength of the "shareHostListNFS" text field to whatever you want and it will save just fine. So the probem seems to only be in the front-end HTML, shame it has not been fixed yet should be a 3 second fix.
There seems to be some limit on the length of the rules you can specify in the web UI for an NFS share (Share --> NFS Security Settings --> Rule). I have ALLOT of linux machines that mount shares and need to specify more rules than is allowed. It seems to work fine if I put them in the exports file but any changes made via the UI truncates the rules again. Is there someway around this limitation?