Expandable Data table does not have grey divider in Firefox

[SpencerReynolds18]

Detailed description

In Chrome and Safari, there is a grey divider line to separate rows. It does not display in Firefox.

Is this issue related to a specific component?
Data Table

What did you expect to happen? What happened instead? What would you like to see changed?
I expected to see a grey line between rows in firefox.

What version of the Carbon Design System are you using?
Carbon Design Website

Expandable Data Table on Chrome. (Also checked Safari and it looked fine there as well)

Expandable Data Table on Firefox