Extra spaces added to the cell which makes the column looks empty.

[MikeAlhayek]

I have been trying recreate the same issue on a fiddler to explain the problem but a different problem is preventing me from doing so. Here is the fiddle to give you at least the html code that I am using https://jsfiddle.net/DTcHh/28806/

Here is a screenshot of the exact file the I downloaded "Columns D-Q appears to be empty columns"

After expanding column "F" or any column between D-Q you'll see the data.

Also, you may want to convert any <br> or <br /> to a new line when exporting html code.

[MikeAlhayek]

What seems to be causing this problem are the whitespaces in the HTML code.

So this causes the problem

<th class="text-center">
    Monday<br>
    01/16/2017
</th>

But making the html code look like this fixes the problem.

<th class="text-center">Monday<br> 01/16/2017</th>

I would suggest trimming the white spaces. Also, convert
to new line in excel.

[clarketm]

Thanks to @boonep and his much appreciated PR, this patch has been applied and will be slated for the v3.3.8 release.