Build OK but runs only with valgrind

Hi There
I'v checked out latest MLT and KDEnlive (FFmpeg from opensuse repos).

mlt is 7.7, kdenlive is v0.8.2-270-g1988023

The build process is ok, but when i start kdenlive from command line i get this:

kdenlive: malloc.c:3096: sYSMALLOc: Assertion `(old_top == (((mbinptr) (((char *) &((av)->bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk, fd)))) && old_size == 0) || ((unsigned long) (old_size) >= (unsigned long)((((__builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 * (sizeof(size_t))) - 1)) & ~((2 * (sizeof(size_t))) - 1))) && ((old_top)->size & 0x1) && ((unsigned long)old_end & pagemask) == 0)' failed.
KCrash: Application 'kdenlive' crashing...
KCrash: Attempting to start /usr/lib/kde4/libexec/drkonqi from kdeinit

running KDEnlive from valgrind actually starts the software (very slowly)

What's that about?