Keep in mind that ES 1.3.9 is where a bunch of things were changed. ES 1.3.10 was a quick release to fix 2 other issues. You can view the ES 1.3.9 change log here:
http://stackideas.com/changelog/easysocial?version=1.3.9
So if changing to ES 1.3.9 doesn't fix the issue, going to ES 1.3.8 might (and is much more likely to if it's the new updates creating this issue). I suggest you create a test site, I'm sure you've seen me post mine (test.alpineascent.com). I literally copy the database and the files from the real site and create and "paste it" over to the test sub-domain. I have to of course create a new database and associate the index.php file to the new database. This allows me to not only see issues in advance before upgrading the live site but also allows for easy access for the stacked team to test things without worrying about going backwards. If you need any help with this, you have my contact info. With any major web project that does regular upgrades it is highly advised that you have a test site. Yes it's a little more work considering that you have to upgrade both, but it ensures stability and allows for issues to be identified/solved easier by creating a testing environment. To ensure that Google does not count it as duplicate content I set the robots.txt file to exclude everything in that sub-domain.
Because I make changes to my real site quite often, my old site eventually becomes different from my real site. So every time ES has a major upgrade (ES 1.2 to ES 1.3) I use it as an opportunity to test the betas with my test site and then purge it completely once the next major release is available. This allows for proper staging, accurate testing, and reduces the work load. I do have to re-create my test site every 4-6 months, but it really isn't much work.
I'll end by saying that issues are often (but not always of course) only in specific scenarios which is why a place for the stacked team to test is very important. I found out that the uploader breaks not only on a specific screen resolution width, but the height in combination with a specific template size breaks it. My point is that it took a lot of specific scenarios for the issue to be tracked down.