I hate to engage in "me too" forum activity, but this occured to me as well. I have two forms on my website. I'm able to export all the entries for the first one, but for the second one, I can only export just the basics (like Entries ID, Date Submittted, IP Address, etc.), and it leaves out many of the other fields.
I'm also using the latest 2.8.7 version of the plugin. Do you know when there might be a fix for this? Thanks.