The data seems to be slightly different when processed by the pivot grid

1. Please download the sample project and download this data sample here.
2. Upload the data sample file to a web storage and change the config file to point to the file. I could do this step myself but it seems the bug is not reproduced with all storages. Most of the time the issue is reproduce with google drive for me but never with drop box. So please try different storages.
3. Run the project and when the data is loaded configure the report as shown here.
4. Then scroll to the bottom and check the Hour column values. You should see a few values without a space character as on this screenshot.  

Expected result: All Hour column values should contain a space character between “Hour” word and a corresponding number. For example, “Hour 00”, “Hour 01”, “Hour 02”, etc.
Actual result: Some Hour column values don’t contain a space character but the data file has a space character for all Hour column values.
 
Note, you might have to repeat the steps several time to reproduce the bug. Also there are usually different Hour values affected.
 
Just FYI, I used Chrome Version 56.0.2924.76 (64-bit) to reproduce the issue.