This affects I think every non-swarming configuration:

https://build.chromium.org/p/chromium.gpu.fyi/builders/Win10%20Release%20%28NVIDIA%20Quadro%20M2000%29/builds/197
https://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28AMD%20R5%20230%29/builds/909
https://build.chromium.org/p/chromium.gpu.fyi/builders/Win10%20Release%20%28Intel%20HD%20530%29/builds/241
https://build.chromium.org/p/chromium.gpu.fyi/builders/Mac%20Pro%20Release%20%28AMD%29/builds/159

Not sure which lines of the log are relevant. They also say recipe_engine_bug:

Traceback (most recent call last):
  File "/b/rr/tmpV8EWoN/rw/checkout/scripts/slave/.recipe_deps/recipe_engine/recipe_engine/util.py", line 150, in raises
    yield
  File "/b/rr/tmpV8EWoN/rw/checkout/scripts/slave/.recipe_deps/recipe_engine/recipe_engine/run.py", line 385, in run_step
    self._close_through_level(step_config.nest_level)
  File "/b/rr/tmpV8EWoN/rw/checkout/scripts/slave/.recipe_deps/recipe_engine/recipe_engine/run.py", line 360, in _close_through_level
    cur.step_result.presentation.finalize(cur.open_step.stream)
  File "/b/rr/tmpV8EWoN/rw/checkout/scripts/slave/.recipe_deps/recipe_engine/recipe_engine/types.py", line 153, in finalize
    l.write_split(line)
  File "/b/rr/tmpV8EWoN/rw/checkout/scripts/slave/.recipe_deps/recipe_engine/recipe_engine/stream.py", line 36, in write_split
    for actual_line in string.splitlines() or ['']: # preserve empty lines
AttributeError: 'list' object has no attribute 'splitlines'

Also the failure mode seems to have shifted from purple to red last night at some point:

https://build.chromium.org/p/chromium.gpu.fyi/builders/Win10%20Release%20%28NVIDIA%20Quadro%20M2000%29/builds/213

These failing steps now have the feature "exception_during_checking_json_local_isolated" which lists:

Traceback (most recent call last):
  File "C:\b\rr\tmpktqpbm\rw\checkout\scripts/slave\recipe_modules\chromium_tests\steps.py", line 1189, in has_valid_results
    self.failures(api, suffix)
  File "C:\b\rr\tmpktqpbm\rw\checkout\scripts/slave\recipe_modules\chromium_tests\steps.py", line 1200, in failures
    return self._test_runs[suffix].json.output['failures']
KeyError: 'failures'

Andrii do you think this is a change in the recipes somewhere?