I'm guessing there is something unique and unexpected in the loaded midi file.

For example, where the midi channel and patch assignments are located within a midi file can change how accurate a midi file is read. The assignments might be located with the midi data or inside the midi file header.

Most programs can read assignments in either location which is why some programs prefer to write midi files using one location while other programs prefer the other.

RealBand and Band-in-a-Box seem to achieve the most accurate results when the assignments are located in the midi data.

A "trick" you can try is to load the midi file into another program and then save the midi file under another name. The new file may modify the file enough for RealBand to read the new file correctly.

Another "trick" to try is to save the midi file under a different midi file format. Most programs can save a midi file as a format "0" or "1" midi file.

Format 0: the MIDI data is represented in a single track, though perhaps using several MIDI channels.

Format 1: the MIDI data is represented by multiple tracks, all synchronized to a common time representation where the first track provides a tempo map.

Jim Fogle - 2025 BiaB (Build 1128) RB (Build 5) - Ultra+ PAK
DAWs: Cakewalk Sonar - Standalone: Zoom MRS-8
Laptop: i3 Win 10, 8GB ram 500GB HDD
Desktop: i7 Win 11, 12GB ram 256GB SSD, 4 TB HDD
Music at: https://fogle622.wix.com/fogle622-audio-home