why CPAN::Reporter::Smoker restarts?

[Alceu Rodrigues de Freitas Junior via cpan-testers-discuss]

Hello folks,

I would like to share my experience with you regarding using 
CPAN::Reporter::Smoker for a while already: I noticed it regularly 
restarts testing the same distributions over and over.

Is there any particular reason for that?

I tried several combinations of parameters like 
trust_test_report_history, but it keeps restarting. Is there any 
relation with clean_cache_after option?

Thanks!

Alceu