I've no idea if they're related; but gimp-2.9 is currently crashing with:

*WARNING*: missing babl fast path(s) between formats "R'G'B'A u16" and "A double"
*WARNING*: missing babl fast path(s) between formats "R'G'B'A u16" and "HSVA float"
*WARNING*: missing babl fast path(s) between formats "R'G'B'A u16" and "HSVA float"
*WARNING*: missing babl fast path(s) between formats "R'G'B'A u16" and "HSVA float"
*WARNING*: missing babl fast path(s) between formats "R'G'B'A u16" and "HSVA float"
*WARNING*: missing babl fast path(s) between formats "HSVA float" and "R'G'B'A u16"
/home/richard/Software/gimp-git/gimp/app/.libs/lt-gimp-2.9: fatal error: Segmentation fault
/home/richard/Software/gimp-git/gimp/app/.libs/lt-gimp-2.9 (pid:21497): [E]xit, [H]alt, show [S]tack trace or [P]roceed: s #0 0x00007f676f440f7b in waitpid () from /lib/x86_64-linux-gnu/libpthread.so.0 #1 0x00007f676f975ed3 in g_on_error_stack_trace ( #2 0x00007f676f976054 in g_on_error_query ( #3 0x000000000049467e in gimp_eek ( #4 0x00000000004948a6 in gimp_fatal_error (message=) #5 0x0000000000494fd7 in gimp_sigfatal_handler (sig_num=) #6
#7 g_type_check_instance (type_instance=type_instance@entry=0x400f290) #8 0x00007f676fc96d5e in g_signal_emit_valist (instance=0x400f290, #9 0x00007f676fc9800f in g_signal_emit (instance=, #10 0x00007f6770fd4c93 in delayed_emission (data=0x7f672c0008e0) #11 0x00007f676f9a0a9a in g_main_dispatch (context=0x18b74b0) at gmain.c:3148
#12 g_main_context_dispatch (context=context@entry=0x18b74b0) at gmain.c:3813
#13 0x00007f676f9a0e40 in g_main_context_iterate (context=0x18b74b0, #14 0x00007f676f9a1162 in g_main_loop_run (loop=0x3e747e0) at gmain.c:4082 #15 0x00000000004943f2 in app_run (full_prog_name=, #16 0x0000000000493d25 in main (argc=, argv=0x17fb6c0)

I've tried with all the latest pulls of glib, babl, gegl, and gimp; as well as with babl-0.1.28

The crash occurs every time I try and stretch HSV contrast.