Test sentence: A badd word and a new badd word. Press F7. Choose Ignore All or Add to Dictionary. The next "badd" will be reported instead of the completion of the spell checking.
Laszlo Nemeth committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/core/commit/?id=c49543cf31c14d4f94f01620244dd7e3ba0919ea fdo#73917 spelling dialog: don't report fully ignored words again The patch should be included in the daily builds available at http://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: http://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Note: this problem was reported by Gábor Kelemen.