In my experience with 3rd party MIDI fies the fade out data is usually written into the file as MIDI CC data for each track, as suggested in the post above.
For each track of the imported project, open it in the MIDI (key) editor + check the controller lanes at the bottom, check for data points in the “expression” and “main volume” CC lanes (sorry I forget the CC#s, but CCs with data are displayed with an asterisk). Other data added by the file author such as program changes, panning, modulation etc can also present some strange results if you’re playing the part with different instruments or patches to the ones the author used, so they sometimes need tweeking a bit too. Hope that helps.