Sliding Stretch Results in Clicking/Popping/Thumping Sound

**Describe the bug**
I recently upgraded from Version 2.3.3 to Version 3.1.3. The Sliding Stretch feature does not work as well as it previously did:

Normally, the procedure I use for applying the Sliding Stretch feature is as follows:
1. Identify the start and end points for the audio selection that needs stretching
2. Press "Z" to move the cursor to zero crossings and double check to make sure that both channels are at zero
3. Split the audio at the start and end points
4. Highlight the audio between the start and end points and apply the "Sliding Stretch" effect
5. Highlight a small portion of audio before and after the split points and use the "Repair" effect.

Before I upgraded, that procedure worked flawlessly. Now, I hear distinct clicking, popping and occasional thumping noises at the start and end points, even when I only use the "Final Tempo Change %" box. When I zoom in at the start and end points after applying the Sliding Stretch effect, they are no longer at or near zero.

**To Reproduce**
Steps to reproduce the behavior:
1. Unzip and open attached project file.
2. Listen to "Original" track.
3. Listen to "Split" Track and note there are no clicking or popping noises. It is split at the 3.472 second mark and both channels are at zero crossings
4. Listen to "Sliding Stretch" Track and note the clicking and popping noise at the split point. I highlighted from 0.00 to 3.472 seconds and applied a 5% Final Tempo Change using Sliding Stretch.
5. Listen to "Repair" track and note the continued clicking and popping noise at the split point. I highlighted .001 seconds before and after the split point. However, the clicking and popping noise persists.

**Expected behavior**
After applying my routine procedures, there should not be any clicking or popping noises at the split point.

**Screenshots**
N/A - See attached project file

**Additional information (please complete the following information):**
- OS: Windows 10
- Version: Audacity 3.1.3
- Sound Device: Windows WASAPI
[Sliding Stretch Bug.zip](https://github.com/audacity/audacity/files/8192886/Sliding.Stretch.Bug.zip)