Change the line 7169 of /lib/tikilib.php for :
if ($prefs'feature_user_watches' == 'y' && ($prefs'wiki_watch_minor' != 'n' || $minor != true)) {
This was fixed in r14411 by Sylvie Greverend. All current versions are fixed.
To help developers solve the bug, we kindly request that you demonstrate your bug on a show2.tiki.org instance. To start, simply select a version and click on "Create show2.tiki.org instance". Once the instance is ready (in a minute or two), as indicated in the status window below, you can then access that instance, login (the initial admin username/password is "admin") and configure the Tiki to demonstrate your bug. Priority will be given to bugs that have been demonstrated on show2.tiki.org.