Looking further, the test:

is($rs->result_source->schema, $s->schema, 
"belongs to the same schema");
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Fails with the message:

#   Failed test 'belongs to the same schema'
#   at t/0200_db/0200_dbconnect.t line 52.
#          got: 'My::Schema::Class'
#     expected: 'My::Schema::Class=HASH(0x8a163c4)'
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It appears to be saying that one is a string and the other is a hash...

And indeed, $rs->result_source->storage is undefined.