I have a single track project, 2:34:00 long. There are 54 bookmarks (labels). I am using “Export Multiple” to create MP3s. Options: Constant Bit Rate (128 kbps), Fast Speed, Joint Stereo Channel Mode. The file is split using Labels. (No audio is included before first label.) They are named “Using Label/Track Name”.
52 of the 54 files tha result are as expected. But two of the files end up being about 400KB in size and 0:00 in play length, while the expected size is about 2KB and several minuts of play length.
Looking carefully at the track, I see nothing remarkable about these two labelled sections. There is nothing unusual about the bookmark names, the length, or anything else I can think of. I can’t figure out why all the other labelled sections result in properly created MP3s, but not these two.
Audacity 2.1.3 (obtained from .exe)
Windows 10 Home, Version 1709 (Fall Creators Update), OS Build 16299.19
If so, have you inadvertently nudged the little grabber triangle (of the 16th and 33rd labels). Doing that can turn a point label into a rage label, sometimes a very short range label which you would only see zoomed-in extremely close.
And note it is almost impossible to turn range labels back into point labels - so if this is the case just add another point label there and delete the short range label (right click in the label and select Delete Label from the dropdown menu).