Data::Alias was generally broken in 5.18.x (CPAN Testers Reports confirm this).
This seemed to affect quite a few people: there've been a number of posts about this.
Version 1.17 of Data::Alias appears to have fixed the problem; again, CPAN Testers Reports seem to confirm this.
My fellow monks
Can't tell (I'm NSA/FBI/HS/...)
Others (explain your deviation)
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