What is the difference between a!apply and a!applycomponents? According to

To clarify, apply() cannot be used with rules or functions that store local data, including rules using load() and certain SAIL components. That is, the state of a SAIL component which stores local data can be preserved with a!applyComponents(), however in these cases, apply() will return an error. In summary, use a!applyComponents() any time you're iterating over a list of components or iterating over a rule that has a load() within it, otherwise use a!apply().

To clarify, apply() cannot be used with rules or functions that store local data, including rules using load() and certain SAIL components. That is, the state of a SAIL component which stores local data can be preserved with a!applyComponents(), however in these cases, apply() will return an error. In summary, use a!applyComponents() any time you're iterating over a list of components or iterating over a rule that has a load() within it, otherwise use a!apply().