Hi
When "Audio format for new recordings" is set to "MP3 (encoder by LAME project)", the mode is CBR, and Bitrate is set to 32kbps in the project setting, the recordings are automatically saved in MPEG-2 Layer 3. Hence, the recording is accordingly resampled from 16kHz, 22.05kHz, or 24kHz. That is, the recorded item file(.mp3) is stored in 16k, 22.05 or 24kHz sample rate. This is undesirable.
Since 32kbps bitrate is supported in MPEG-1 Layer 3 and it has higher sample rates like 32kHz, 40kHz, or 48kHz, it should use MPEG-1 instead.
One more issue. When the mp3 item is resampled, the waveform disappears after recording is punched out. Have a look at the video clip here:
If I switch to another application and the item becomes offline and back again, the waveform appears again.
I think these have something to do with how reaper uses lame mp3 library.
My setting : Windows 10 & Reaper v5.50pre9/x64