Proper bug reports should be done in Mantis but I think the forum section fills a need in that people can bring up things that they think are bugs and discuss them without having to register and properly file a bug at Mantis.
Perhaps they are not bugs at all?, people can give them advise and solutions. If and when it's clear that it is a bug the reporter can be asked to file a proper bug report at Mantis.
With this angle I think the section can be renamed to bug discussion. Calling it bug reports is a bit misleading since bugs really shouldn't be reported there...
Links:
[1] http://kdenlive.org/forum/contribution-forums/website-development