Multiple log entries when using Rails.cache

I've started using Rails.cache, specially Rails.cache.fetch. This gives
me some log entries I'm a little curious about - I hope someone can poke
me in the right direction.

Examples:

1.
Rails.cache.write('testing', 'test value')
Rails.cache.read('testing')

Gives these log entries:

Cache write: testing
Cache write: testing
Cache read: testing
( Why the two writes? )

2.
Rails.cache.fetch('testing') { 'test value' }

Gives these log entries:

Cache read: testing
Cache write: testing
Cache miss: testing ({})
Cache write: testing
Cache write (will save 0.00ms): testing
( Miss after it is writtin? And then to extra writes? )

Best regards
Rudi