Gridlines do not show up in "Current Fields" Excel view

As in issue JRA-6567, the new version of Excel current fields output produces output where Excel no longer has visible gridlines. I have been patiently waiting for version 3.3.1 to be released so I could train users on getting an Excel output, and now this problem has re-appeared. Can you please provide a patch (I'm used to customizing my jsp file now) to fix this?

This was working fine in version 3.3 and now appears to be broken in version 3.3.1 and the problem is reproducible on jira.atlassian.com. To see the problem, just export any filter to Excel. It is very hard to read without those gridlines.

I compared the navigator-excel-current.jsp files between 3.3 and 3.3.1 and the only difference was a valid one - for issue JRA-7598. So, I wonder if the problem is from another changed file?