YAML Error in t/eval.t

[eserte]

On some of my smoker systems the test suite fails like this:

YAML Error: Invalid characters in stream. This parser only supports printable ASCII
   Code: YAML_PARSE_ERR_BAD_CHARS
   Line: 0
   Document: 0
 at /home/cpansand/.cpan/build/2019072207/YAML-1.29-0/blib/lib/YAML/Loader.pm line 36.
# Looks like your test exited with 1 before it could output anything.
t/eval.t ............. 
Dubious, test returned 1 (wstat 256, 0x100)
Failed 9/9 subtests 

Unfortunately I don't see why it is failing --- it does not seem to be caused by YAML 1.29, as there are configurations where it's passing with this YAML.pm version.