I have bean using Infuse and Plex for many years and not had this issue until recently so not sure when the change in behavior was introduced.
When playing a movie or tv series that has multiple audio streams for different languages Infuse is selecting the wrong stream (non English) to play back. Plex plays the correct stream (English) and it is marked as t he default in Plex.
I don’t seem to be able to manually an audio stream in Infuse so I cant work around it and have to fall back to using the Plex client.