I tried to export my S5B song to NSF and listen to it in NSFPlay 2.6, but the pitch of the 2A03 pulse0 got stuck in A-1, the lowest frequency possible.

Here's an example. I tested in a fresh .dnm file with the pulse0 and 5b square1 playing together the exact line, but the pulse0 does not respond. Why?

Then I tried to convert it in another version of famitracker: the beta 0.5 and Hertzdevil 0CC one. These two work properly when exporting to NSF, except for Dn.

Here's a ZIP file with the test that I did:
BUG test.zip