V1.0.22 Win7 64/32
If ID3v1 tags are not enabled alongside all others, then any file encoded (tested with FLAC and WAV) into mp3 using LAME 3.99.5 will be slightly shortened at the end compared to the original file. This can be easily seen in tracks on CDs that are supposed to flow into the next one. Exact measure of time(data) lost is a little difficult to determine, but small; measured using Audacity after aligning, due to LAME adding a bit of silence at the beginning of the track, and zooming into original file and converted one in parallel.
It would seem that the issue can be fixed by editing ID3v1 tags, without necessarily removing others, into converted file using a dedicated, separate, program. It is, however, something that does affect the sound at the end of the file if submitted to playback on dedicated players.
Custom test settings (these I use, but have tested with a couple presets with the same result)
-set quality 0
-only Original bit enabled
-Temporal masking enabled
-Auto output sampling rate
Note: haven't found any information about this error being native to LAME, though the possibility exists, and I have yet to test the compiled (rarewares bundle) LAME to contrast.