FreeBoy creating noise

I was going to post a bug report when I found that it might be related to this issue:
~~Version 1.1.3 (Ubuntu @17.04)~~
Also with the newest build from master.

When changing notes, FreeBoy often emits a noise, even though all channels except for Channel 2 are muted.


The picture above shows, how it should look like (approx.) and how it looks by lmms.
(The upper picture was taken with gbsplay by playing the "nearly" same file, with all other tracks muted as well.)

I don't know if this is intended, but not hearing this with VLC which also uses Game Music Emu (granted, I can't mute the other channels so I can't be 100% sure), I guess this is an issue.

EDIT: Also tested by using pasuspender and switching to alsa.

The following is the same wave as above, rendered with the current version of lmms creates even more noise.
I've noticed even a small noise is audible when releasing a note.
(37f6032b4da23b712f4fbc76e930936c08986493)


Start by reproducing the noise in FreeBoy with all channels except Channel 2 muted, including when changing and releasing notes. Compare the rendered waveform with the gbsplay example and the current LMMS render. Done means the unintended noise is no longer audible in those cases.

Written by the indexing model from the issue text.