How does AnCom solve the temporal division of labor problem? Presumably no one wants to live in a cave. Take a pencil, for example. To manufacture it requires a rubber tree farm, a logging territory, a graphite mine, and an aluminum mine, along with a place to put it all together. Obviously a pencil manufacturer cannot be in 4-5 places at once, and since AnComs do not believe in absentee ownership of property, as soon as the owner left one property to tend to another property, the workers would steal all the land and equipment, or claim it as their own. So how does anything get made in AnCom beyond hand-made bead necklaces?
The question is wrong in its attempt to explain anarcho-communist approaches to social production, as such the question is unanswerable. This will be an attempt to answer what the question should be.
Social production of useful objects is an inherently social phenomena. Pencils are never produced in isolation or on Walden Pond. They are always produced in a context of water, power, machinery, raw materials, ancillary materials, human effort and human thought. These elements of social production are brought together in any economy in order to produce.
The general anarcho-communist conception of productive and useful activity involves limited spans of control within socially delegated or accepted purposes: some people choose to make pencils, and other people agree that they should. Agreeing that some people should make pencils is also an agreement that the materials and machinery for this purpose should be supplied.
The supply of purposeful material in anarcho-communist economic conceptions is driven by voluntary donation or supply. Even considering this as zero-priced is somewhat silly, the mechanisms of distribution are throughput and discussion centered, a mixture of excess and what's easiest understood as democratic, but not central, planning.
Pencil makers give their effort and creativity and pencils away for people who want pencils. The pencil inputs makers give their effort and creativity and services and products away.
The idea of "theft" in this context is meaningless, as is "claiming it as their own," because one of the central claims of anarcho-communism is that property as a social relation of exclusive and exclusionary control over socially productive resources can be abolished, and relationships of gift and voluntarism can replace all these activities.
For concrete examples of this kind of behaviour, most work-ins and productive factory occupations give an example, as do the limited circumstances of revolutionary production.
And so, to resolve the question in the title at the end:
The temporal division of labour is resolved by a priceless giving based economy and by the discussion to resolution of the organisation of useful activity as throughput relationships. These can be seen in prefigurative forms in the relationships between industry workers councils during revolutions in the 20th century, Hungary is a great though time limited example.
Whether such an set of human relationships is desirable tends to vary based on your opinions about property. Whether such a set of human relationships results in greater value production is a clear negative: value is abolished. Whether such a society expands faster than capitalism is unclear: most have been shut down by military force.