Unrelated, and not clear if you've encoded these files yourself, but these LAME settings are a bit odd:
Encoding settings : -m j -V 2 -q 3 -lowpass 19 --vbr-old -b 128
Joint stereo is enabled by default, so
-m j won't do anything.
Variable Bit Rate is enabled with
-V 2, but then
-b 128 sets the minimum to 128 kbps.
(
-V 2 would give a bitrate around 192 kbps, so the only thing dropping lower than 128 is probably silence, though I haven't tested this)
I'm not sure if there's a reason to be using
--vbr-old in 2024, and using it with
-q 3 may create sub-optimal results.
Of course, at ~192 kbps, anything the other settings do probably won't affect transparency anyway, so... [shrug]
Bee excellent to each other...