[NTG-context] different behavior between xetex and luatex

Hi, all. I expect different output in xetex and luatex using context. and I think the problem is quite serious although I do not speak Turkish. in turkish, fi can not be treat as ligatures and I can see luatex handle that quite well. however, in xetex, fi are treated as ligatures. I attach the files and output here. I don't know it is a bug in xetex, context or dvipdfmx:( Yue Wang