Random Penny Added While Playing Slots

Hi! I have been playing slots since about 2015 and as I have learned a strategy, I have also noticed some trends the machine has. After about 45 minutes to an hour of playing the same $2 slot machines, a random penny (or two) will be added to my account and I cannot figure out why. Does anyone know what this $0.01 meams? It’s like the machine is tracking how long I have been playing or sensing a particular pattern I am using.