`bandit -rf custom` only shows up to 3 warnings

Describe the bug
Running bandit with -rf custom seems to output a maximum of three warnings (no matter how many there are).

To Reproduce
Steps to reproduce the behavior:

1. Clone bandit
2. Run bandit -rf custom examples (on the provided examples directory)

Output

$ bandit -rf custom examples                                                                                                                                                   <<<
[main]  INFO    profile include tests: None
[main]  INFO    profile exclude tests: None
[main]  INFO    cli include tests: None
[main]  INFO    cli exclude tests: None
[main]  INFO    running on Python 3.6.8
84 [0.. [manager]       ERROR   Exception occurred when executing tests against examples/nonsense2.py. Run "bandit --debug examples/nonsense2.py" to see the full traceback.
50.. ]
/Users/robert.grant/projects/bandit/examples/assert.py:1: B101[bandit]: LOW: Use of assert detected. The enclosed code will be removed when compiling to optimised byte code.
/Users/robert.grant/projects/bandit/examples/binding.py:4: B104[bandit]: MEDIUM: Possible binding to all interfaces.
/Users/robert.grant/projects/bandit/examples/cipher-modes.py:6: B305[bandit]: MEDIUM: Use of insecure cipher mode cryptography.hazmat.primitives.ciphers.modes.ECB.

Expected behavior
I would expect to see all security errors identified, in a one-per-line format.

Bandit version

bandit 1.5.1
  python version = 3.6.8 (default, Feb 12 2019, 17:27:09) [GCC 4.2.1 Compatible Apple LLVM 10.0.0 (clang-1000.10.44.4)]

Additional context
I use the examples folder here, which seems to contain bad files on purpose (generates the ERROR above). I see the same behavior on another directory without bad files.

Thanks!

Reproduce the issue with bandit -rf custom examples, then rerun with bandit --debug examples as suggested in the report. Trace the command's reporting path and the handling of examples/nonsense2.py; done means every identified security error is emitted one per line rather than only three warnings.