manticore sometimes reports "overflow" for "underflow or "overflow/underflow"

OS / Environment

Description: Ubuntu 18.04.1 LTS Release: 18.04 Codename: bionic

Manticore version

Version: 0.2.0

Python version

Python 3.6.

Dependencies

asn1crypto==0.24.0 atomicwrites==1.1.5 attrdict==2.0.0 attrs==18.1.0 capstone==3.0.5 certifi==2018.4.16 cffi==1.11.5 chardet==3.0.4 click==6.7 coincurve==8.0.0 configparser==3.5.0 coverage==4.5.1 cytoolz==0.9.0.1 dictionaries==0.0.1 eth-abi==1.1.1 eth-account==0.3.0 eth-hash==0.1.4 eth-keyfile==0.5.1 eth-keys==0.2.0b3 eth-rlp==0.1.2 eth-tester==0.1.0b29 eth-utils==1.0.3 ethereum==2.3.2 -e git+git@bitbucket.org:rockybernstein/evm-bytecode.git@80855f3eb9f8c5f7240f63d63f7c54ff19f59860#egg=evm_bytecode flake8==3.5.0 future==0.16.0 hexbytes==0.1.0 hypothesis==3.0.0 idna==2.7 Jinja2==2.10 manticore==0.2.0 markdown2==2.3.5 MarkupSafe==1.0 mccabe==0.6.1 mock==2.0.0 more-itertools==4.2.0 mythril==0.18.11 nose==1.3.7 parsimonious==0.8.0 pbkdf2==1.3 pbr==4.2.0 persistent==4.2.4.2 pkginfo==1.4.2 pluggy==0.6.0 ply==3.11 plyvel==1.0.5 py==1.5.4 py-ecc==1.4.3 py-flags==1.1.2 py-solc==3.1.0 pycodestyle==2.3.1 pycparser==2.18 pycryptodome==3.6.4 pyelftools==0.24 pyethash==0.1.27 pyevmasm==0.1.0 pyflakes==1.6.0 Pygments==2.2.0 pygments-lexer-solidity==0.3.1 PyQt5==5.11.2 PyQt5-sip==4.19.11 pysha3==1.0.2 pytest==3.6.3 pytest-cov==2.5.1 pytest-mock==1.10.0 pytest-qt==2.4.1 pytest-runner==4.2 PyYAML==3.13 repoze.lru==0.7 requests==2.19.1 requests-toolbelt==0.8.0 rlp==1.0.1 scrypt==0.8.6 semantic-version==2.6.0 six==1.11.0 toolz==0.9.0 tqdm==4.23.4 transaction==2.2.1 twine==1.11.0 unicorn==1.0.1 urllib3==1.23 -e git+git@github.com:rocky/python-xdis.git@c77847dd466c9f9a34310346b6ea6c67c3989ae0#egg=xdis z3-solver==4.5.1.0.post2 zope.interface==4.5.

Summary of the problem

Step to reproduce the behavior

$ cd ethereum-analyzer-suites-runner
$ manticore --detect-all benchmarks/Suhabe/benchmarks/integer_overflow_minimal.sol 

Look in mcore's global.findings

Expected behavior

- Unsigned integer underflow at SUB instruction -

or

- Unsigned integer overflow/underflow at SUB instruction -

Actual behavior

- Unsigned integer overflow at SUB instruction -