Slip Tool and Audio Overlap Fades Not Functioning Correctly

Issue Description:
The Slip Tool and standard audio overlap fade behavior are not working correctly. Both tools respond inconsistently and appear functionally broken.
Details:
Slip Tool: Does not reliably slip clip content within fixed in/out points. Behavior is erratic and inconsistent with expected functionality.
Audio Overlap Fades: Creating fades by overlapping audio clips (dragging the end of one clip into another) no longer works as expected. Overlaps fail to form properly or behave unpredictably.

Also, when I add a cut on any clip in the stringouts sequence, it shows 'Duplicate Frame Markers'

P.S: This is just happening on one specific project.