I believe I found a fix for when songs loop, but get turned to Tempo 1 and potentially similar problems

[Den1604]

I tested out the exact same midi in both the newer mamar and the older version, upon investigating them i realized that newer Mamar has multiple Delay(x) in the first track, while old mamar compiles them into one big Delay of (presumably) all of them combined
my best guess is that this is what causes the issue, either way this shouldn't hurt changing (and i assume it would not be too hard to fix, even if it does not end up fixing the problem)

[bates64]

The reason for this difference is that decoding contiguous delays into a single, long Delay is lossy. Consider the following input situation:

Delay(200)
Delay(200)
Delay(200)

Under the old system, this would get turned into Delay(600). When encoding, Delay(600) is valid to output (600 < 2032), which would then make the output not match the input. Matching input/output is a hard requirement - there are tests for it - so the decision was made to not combine contiguous delays when decoding.