decode-bad-stack test failing (non-det) with "instr_encode_error: operands invalid"

[derekbruening]

AFAIK nobody has ever seen this before:

https://travis-ci.org/DynamoRIO/dynamorio/jobs/204498268

93/263 Test  #92: code_api|security-common.decode-bad-stack ........................***Failed  Required regular expression not found.Regex=[^Bad instr about to happen
Got an illegal instruction
$
]  0.38 sec
Bad instr about to happen
<Application /home/travis/build/DynamoRIO/dynamorio/build_debug-internal-32/suite/tests/bin/security-common.decode-bad-stack (16208) DynamoRIO usage error : instr_encode error: operands invalid>
<Usage error: instr_encode error: operands invalid (/home/travis/build/DynamoRIO/dynamorio/core/arch/x86/encode.c, line 2350)
version 6.2.17220, custom build
-no_dynamic_options -code_api -stderr_mask 12 -stack_size 56K -max_elide_jmp 0 -max_elide_call 0 -early_inject -emulate_brk -no_inline_ignored_syscalls -native_exec_default_list '' -no_native_exec_managed_code -no_indcall2direct 
0x476de9e4 0x5673a9b3
0x476dea1c 0x56885b9b
0x476deac0 0x5687be89
0x476deae8 0x56867dc5
0x476deb30 0x56869928
0x476deb4c 0x56732fe6
0x476dee14 0x5673a3d1
0x476dee44 0x5689fc2a
0x476def68 0x56722f8a
0x476deff4 0x47699f87
0xffb2cf88 0xf753dad3>

[geoste01]

Another failure, same error message: https://travis-ci.org/DynamoRIO/dynamorio/jobs/229140851