Steps to reproduce:
# Create a translatable page with at least one section
# Mark it for translation
# Translate a unit to some language
# Make change to the translatable page with that section you translated
# Mark the page for translation, do **not** check "skip fuzzy" checkbox
# Update the now fuzzy translation to "something else"
# Now mark the updated translation with !!FUZZY!! and save
Observed: the translation page still contains "something else". By normal rules it should contain the source text.
I didn't have time to check, but steps 4-6 could possibly be skipped with the same result.