Line x is out of index, last available: y

[slootjes]

Trying to use this great looking library but when trying the browser vanilla example I get these errors on every file I try:

Uncaught Line 3051 is out of index, last available: 3047
Uncaught Line 34635 is out of index, last available: 34627
Uncaught Line 256 is out of index, last available: 255

Any idea? Weirdly enough the example from jsfiddle does work fine but it seems to be using an older version of the code where the percentage is actually the chunk of data.

Browser: Chrome v65.0.3325.181