First, I'd update. You're many many builds behind. The issue may be fixed.
Second, the box isn't crashing (there's no crash data). It could be a build issue with that build (we did have some builds in Feb/March that didn't create crash data on a crash).
Third, if there is a BIOS (or IPMI) update I would recommend you upgrade.
Fourth, I saw these entries:
arning: KLD '/boot/kernel-debug/profile.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/systrace_freebsd32.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/systrace.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/sdt.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/lockstat.ko' is newer than the linker.hints file
link_elf_obj: symbol _mtx_assert undefined
linker_load_file: Unsupported file type
KLD dtraceall.ko: depends on fasttrap - not available or version mismatch
linker_load_file: Unsupported file type
ahcich5: Timeout on slot 1 port 0
ahcich5: is 00000000 cs 00000002 ss 00000000 rs 00000002 tfd 58 serr 00000000 cmd 0000c117
ahcich4: Timeout on slot 15 port 0
ahcich4: is 00000000 cs 00008000 ss 00000000 rs 00008000 tfd 58 serr 00000000 cmd 0000cf17
ahcich3: Timeout on slot 21 port 0
ahcich3: is 00000000 cs 00200000 ss 00000000 rs 00200000 tfd 58 serr 00000000 cmd 0000d517
ahcich2: Timeout on slot 31 port 0
ahcich2: is 00000000 cs 80000000 ss 00000000 rs 80000000 tfd 58 serr 00000000 cmd 0000df17
ahcich1: Timeout on slot 24 port 0
ahcich1: is 00000000 cs 01000000 ss 00000000 rs 01000000 tfd 58 serr 00000000 cmd 0000d817
ahcich0: Timeout on slot 24 port 0
ahcich0: is 00000000 cs 01000000 ss 00000000 rs 01000000 tfd 58 serr 00000000 cmd 0000d817
warning: KLD '/boot/kernel-debug/profile.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/systrace_freebsd32.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/systrace.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/sdt.ko' is newer than the linker.hints file
warning: KLD '/boot/kernel-debug/lockstat.ko' is newer than the linker.hints file
link_elf_obj: symbol _mtx_assert undefined
linker_load_file: Unsupported file type
KLD dtraceall.ko: depends on fasttrap - not available or version mismatch
linker_load_file: Unsupported file type
ahcich5: Timeout on slot 31 port 0
ahcich5: is 00000000 cs 80000000 ss 00000000 rs 80000000 tfd 58 serr 00000000 cmd 0000df17
ahcich4: Timeout on slot 12 port 0
ahcich4: is 00000000 cs 00001000 ss 00000000 rs 00001000 tfd 58 serr 00000000 cmd 0000cc17
ahcich3: Timeout on slot 5 port 0
ahcich3: is 00000000 cs 00000020 ss 00000000 rs 00000020 tfd 58 serr 00000000 cmd 0000c517
ahcich2: Timeout on slot 2 port 0
ahcich2: is 00000000 cs 00000004 ss 00000000 rs 00000004 tfd 58 serr 00000000 cmd 0000c217
ahcich1: Timeout on slot 14 port 0
ahcich1: is 00000000 cs 00004000 ss 00000000 rs 00004000 tfd 58 serr 00000000 cmd 0000ce17
ahcich0: Timeout on slot 25 port 0
ahcich0: is 00000000 cs 02000000 ss 00000000 rs 02000000 tfd 58 serr 00000000 cmd 0000d917
The warnings pretty much imply that either you've modified the OS, or the OS has some kind of corruption. Likewise if you've enabled the debug kernel, you've probably made your system less reliable as a result.
Other than those 4 things I don't have anything else to go on. Nothing "looks" wrong.