I have a KitchenAid refrigerator (ksss42qdx05). A few weeks ago, I noticed that the temperature in the freezer got higher than before. I purchased a wireless temperature sensor and logged the temperature. I see that the freezer has a defrost cycle every 10 hours, and the temperature increased from 0~6 degrees to 15-20 degrees. After the defrost cycle ended, the temperature drops somewhat fast to 10 degrees and then took another 6-8 hours to come down to where it was. When the temperature reached at the lowest of the cycle, it was almost time for another defrost. Would you please let me know if this is considered normal? If so, what could be wrong? Thanks in advance.
EDIT: I have already opened the panel and examined the evaporator coil. There was no ice blocking the air inlet nor no built-up ice on the evaporator coil.
The temperature graph can be found here at https://www.dropbox.com/s/ub0w6r5ikxo2raj/Screenshot_20210725-110352_Govee%20Home.jpg