Crash with assertion at random times (app minimized to tray)

I'm using Slackware GNU/Linux 13.1, qbittorrent v2.7.3 with libtorrent-rasterbar v0.15.5. App tends to crash from time to time, rather rarely (once in several hours), but without any specific reason -- just working in background, app minimized to system tray, downloading/uploading a few files. I got this from X display manager log:

qbittorrent: malloc.c:3951: __libc_valloc: Assertion `!p || ((((mchunkptr)((char*)(p) - 2*(sizeof(size_t)))))->size & 0x2) || ar_ptr == (((((mchunkptr)((char*)
(p) - 2*(sizeof(size_t)))))->size & 0x4) ? ((heap_info *)((unsigned long)(((mchunkptr)((char*)(p) - 2*(sizeof(size_t))))) & ~((2 * (512 * 1024))-1)))->ar_ptr :
 &main_arena)' failed.

*************************************************************
Catching SIGABRT, please report a bug at http://bug.qbittorrent.org
and provide the following backtrace:
qBittorrent version: v2.7.3
stack trace:
  [0xffffe400]
  /lib/libc.so.6 : gsignal()+0x47 [0xb627ba67]
  /lib/libc.so.6 : abort()+0x182 [0xb627d2e2]
  /lib/libc.so.6 : __libc_valloc()+0x140 [0xb62c5d10]
  /usr/lib/libtorrent-rasterbar.so.6 : libtorrent::page_aligned_allocator::malloc(unsigned int)+0x1d [0xb74d89cd]
  /usr/lib/libtorrent-rasterbar.so.6 : boost::pool<libtorrent::page_aligned_allocator>::ordered_malloc_need_resize()+0x5a [0xb7504c5a]
  /usr/lib/libtorrent-rasterbar.so.6 : libtorrent::disk_buffer_pool::allocate_buffer(char const*)+0xa6 [0xb74fa716]
  /usr/lib/libtorrent-rasterbar.so.6 : libtorrent::piece_manager::hash_for_slot(int, libtorrent::partial_hash&, int, int, libtorrent::big_number*)+0x2e9 [0xb7
5ee989]
  /usr/lib/libtorrent-rasterbar.so.6 : libtorrent::piece_manager::hash_for_piece_impl(int)+0xea [0xb75eed0a]
  /usr/lib/libtorrent-rasterbar.so.6 : libtorrent::disk_io_thread::operator()()+0x16da [0xb750169a]
  /usr/lib/libtorrent-rasterbar.so.6 : boost::detail::thread_data<boost::reference_wrapper<libtorrent::disk_io_thread> >::run()+0x23 [0xb7508193]
  /usr/lib/libboost_thread.so.1.42.0 : thread_proxy()+0x66 [0xb62387b6]
  /lib/libpthread.so.0 : ()+0x5830 [0xb64eb830]
  /lib/libc.so.6 : clone()+0x5e [0xb633015e]