Loop playback starts two measures before the start flag and ends playback two measures before the end flag. I've closed MS and reopened it; no change. I also did a full power down of my computer; still no change. I've attached the file. I use it to help me learn and memorize pieces for my chorus.
The marked loop is from the beginning of m87 through the end of m95.
The staves are marked T1, T2, B1, B2, P, and S, but both the Ts are Trumpet Bb (at concert pitch), both the Bs are Trombone, and the S is another Trombone. I have WIN 11 with an LG Gram.