UMLR — Clarification about Interactions owning Actions and about the semantics of Actions owned by Interactions

In UML 2.5, the summary of the Actions chapter in 16.1 refers to the possibility of an Interaction owning an Action and makes several points:

(1) Actions are contained in Behaviors, specifically Activities (as ExecutableNodes, see Clause 15) and Interactions (see Clause 17). These Behaviors determine when Actions execute (2) and what inputs they have (3). However, the abstract syntax and semantics of Actions are very dependent on Activities (4), because they specialize elements and semantics from Activities to accept inputs and provide outputs and to define Actions that coordinate other Actions (Structured Actions, see sub clause 16.11).

(1) is reflected in figure 17.1

(2) is under-specified.

17.12, ActionExecutionSpecification states:
An ActionExecutionSpecification is a kind of ExecutionSpecification representing the execution of an Action.
17.5.3 semantics of Action Execution Specification states:
ActionExecutionSpecification is used for interactions specifying messages that result from actions, which may be actions owned by other behaviors.

The semantics of ActionExecutionSpecification should be described in 1 place; suggest 17.12.

(3) is a problem because 17.12 + 17.5.3 are insufficient to explain the semantics of ActionExecutionSpecification.

Depending on who owns the Action and of the context classifier for the Action vs. the Interaction, several cases need to be distinguished.
An ActionExecutionSpecification refers to an Action owned by the owning Interaction
An ActionExecutionSpecification refers to an Action owned by an Activity whose context classifier is different than the context classifier of the owning Interaction
An ActionExecutionSpecification refers to an Action owned by an Activity whose context classifier is also the context classifier of the owning Interaction
The first case is severely under-specified.
The last two cases are more complicated because the semantics of ActionExecutionSpecification depends on the semantics of Action owned by an Activity.

In all 3 cases, it is unclear how the message notation in Interactions relates to the input/output pins of actions referred to via an ActionExecutionSpecification.