Freezer freezing up again

In 2012 for my GE side by side refrigerator, my freezer froze up and all the food thawed.
I replaced the following:
WR51X10055
Heater and bracket assembly
WR50X10068
Defrost limiter thermostat

It has worked fine up until now
And now it is freezing up again and all the food is thawing

Are there other parts that could be the problem here?
Or would it be only these 2 parts that I replaced in 2012?