@davesugden while I started this string, I am not having the issue this year. I had assumed the TT had fixed the bug for the online version. I keep checking and the data has held after making changes to other sections (last year this seemed to trigger TT to drop the 8939 data) and its holding. I've also periodically printed/viewed all forms under the tax tools section (bottom left of left hand col on each page) and I see the form. The only bug I see is if I click the "Done with Income" button at the bottom of the "Wages and Income" section TT tries to take me through the steps to submit details of Foreign Accounts even though I've already submitted them. I just back out of this and navigate to other sections using the menu on the left hand bar.
Last year, the "work around" for me was to submit the data once everything else was done and just before you go through the "Review" phase. HOWEVER, if the Review phase requires you update another section, and it often does, then I lost the 8939 data again. So after each change I made, required by the review stage, I went to check the 8939 data and added it again if lost. I had to do this several times, it was incredibly frustrating, but once I made every correction required by the review section and then checked/added the 8939 data for the last time it held and I then immediately file (i did a quick print/view forms check before filing).
Perhaps the only thing I did differently this year is I went straight to "1099-OID, Foreign Accounts" section under Wages & Income and submitted the data that populated 8939, rather than waiting for TT to prompt me, but I can't think that made the difference in terms of the data holding.
