Dell has acknowledged that some early XPS 15 9500 machines shipped with wobbly trackpads. Apparently not meeting the company's "stringent quality and experience standards", Dell is offering to correct affected units. New XPS 15 9500 shipments should not suffer from wobbly trackpads, either.
https://www.notebookcheck.net/Some-early-Dell-XPS-15-9500-machines-have-wobbly-trackpads-but-remediation-is-on-offer-for-affected-units.477550.0.html