I upgraded my WP install and plugins to the latest versions today:
qtranslate-x 3.2.9
ACF 5.2.2
WP 4.1.1
After editing a page which contained some repeater fields (and not touching the repeaters themselves), unfortunately all the repeater fields were emptied after a save.
Saving any page with repeaters renders them empty and lost.
Disabling qtranslate-x allows repeaters to save again, but this is a sincere warning to anyone who upgrades to these versions above as you may lose a significant amount of data if you upgrade to these versions.
Oddly enough, rolling qtranslate-x to 3.2.7 (where it used to work) didn’t solve the problem, neither did rolling ACF back to 5.2.1; I imagine there is an issue with the new ACF release in relation to qtranslate-x and the latest WordPress.
To resolve my data loss I disabled qTranslate-x, went to the affected post and was able to restore a revision that still had the repeater field data. qTranslate-x must still be disabled for this restore to save. After updating, you can reenable qTranslate-x (just not for any writes/updates).
FYI: I created an issue on qtranslate-x’s github tracker, so hopefully we’ll see a fix soon before too many people suffer the same fate: https://github.com/qTranslate-Team/qtranslate-x/issues/119