To register an action ActionProviderService method registerImplementation(...) is called. When using ActionProviderServiceAdapter implementation this method will provide an empty set as action supported operation identifiers (instances).

This prevents us from successfully registering action into DOMRpcRoutingTable.

ActionProviderServiceAdapter#registerImplementation():

https://github.com/opendaylight/mdsal/blob/12879467c0adaecc410b685681af4c2c112b4bca/binding/mdsal-binding-dom-adapter/src/main/java/org/opendaylight/mdsal/binding/dom/adapter/ActionProviderServiceAdapter.java#L72

DOMActionProviderService#registerActionImplementation:

https://github.com/opendaylight/mdsal/blob/12879467c0adaecc410b685681af4c2c112b4bca/dom/mdsal-dom-api/src/main/java/org/opendaylight/mdsal/dom/api/DOMActionProviderService.java#L33

final DOMRpcRoutingTable newTable = (DOMRpcRoutingTable) oldTable.add(implementation, rpcs):

https://github.com/opendaylight/mdsal/blob/12879467c0adaecc410b685681af4c2c112b4bca/dom/mdsal-dom-broker/src/main/java/org/opendaylight/mdsal/dom/broker/AbstractDOMRoutingTable.java#L68