There are two issues here:

• Duration is hidden behind the progress bar
• Duration runs off the end of the stage-wrapper
  

I found I could get a better behaviour by updating the style to:

• Set duration to sit on top
• Set position to relative (to set correct width)
• Set line-height to set correct progress bar height

.jobsTable .stage-cell .stage-wrapper .duration {
  text-align: center;
  position: relative!important;
  line-height: 4.05em;
  padding-bottom: 1em;
  box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.1);
  border-radius: 4px;
  z-index: 1;
}

As seen here:

I also tried changing the stage-cell progress bar opacity. It made it a little more readable but it could be confused with the progress being unknown.

A quick look in chrome shows a similar behaviour:
Before:

After:

And a similar bad behaviour in Safari: