Portions of Split mp3 Repeated

Windows 10 Pro Version 20H2 Build 19042.1466
Audacity Audacity 3.1.3

This seems to happen most, but strangely not all of the time since I installed v3.1.3.

I import a large mp3 (typically 12 or more hours in length) using drag-and-drop
Then I use the Analyze | Regular Interval Labels to create Labels with these settings:

  • Create Labels based on: Number of Labels
  • Number of Labels: 30 (typical)
  • Label Interval (seconds): 1800.00
  • Length of label region (seconds): 1800.0
  • Label Text: some title
  • Minimum Number of digits in Label: 2(After Label)
  • Begin numbering from: 1
  • Message on Completion: Details

Then I use Export Multiple to create the smaller segment files.

The problem is that the tail end, maybe 2 minutes, of the previous file is repeated at the start of the next file.

What am I doing wrong? I get the same thing if I assign the labels based on Label Interval as well.

Uninstalled and reinstalled v 3.0.5: Same problem