the switch seems to work for me with a basic command line.
lame.exe -V 2 -t "TEST.wav" "TEST.mp3"
File name : TEST.mp3
Subsong index : 0
File size : 10.5 MB (11 077 532 bytes)
Last modified : 2022-08-03 15:39:45
Duration : 7:41.546 (20 354 159 samples)
Sample rate : 44100 Hz
Channels : 2
Bitrate : 192 kbps
Codec : MP3
Codec profile : MP3 CBR
Encoding : lossy
Embedded cuesheet : no
<MP3_STEREO_MODE> : joint stereo
lame -V 2 TEST.wav "TEST XING.mp3"
File name : TEST XING.mp3
Subsong index : 0
File size : 10.5 MB (11 077 949 bytes)
Last modified : 2022-08-03 15:40:04
Duration : 7:33.893 (20 016 696 samples)
Sample rate : 44100 Hz
Channels : 2
Bitrate : 195 kbps
Codec : MP3
Codec profile : MP3 VBR V2
Encoding : lossy
Tool : LAME3.100
Embedded cuesheet : no
<ENC_DELAY> : 576
<ENC_PADDING> : 1032
<MP3_ACCURATE_LENGTH> : yes
<MP3_STEREO_MODE> : joint stereo
maybe try the command line without the tagging portion? Maybe adding tags overrules disabling the Xing\Lame tag