Time Machine doing 2 backups per hour?

[I Need a Drink]

I just turned on Time Machine again after not using it for a while. I noticed that when I enter Time Machine it is showing two backups at the exact same time, every hour for the past day. Also since I turned it back on, my computer seems to freeze for a second or two from time to time. Any ideas?

 

[Rok73]

Are we talking about a MacBook or a stationary Mac? Which model exactly?