@boonesmom Two years is a time when they are reaching full maturity, so it is not unusual to have problems with them challenging at that age. When you say you are not around when it happens, that is a good sign. Many do not have the correct authority and understanding of dog body language / posture. It suggests the dog respects your authority.
Some dogs can be difficult, others can become more difficult as they mature past two. Usually by 7-8 they become more easy going, although not always. Dogs have a pack mentality, changes make a difference to their structure. The more you keep to a routine and structure, the better they usually respond.
The other possibility is that the dog doesn’t have enough exercise / mental stimulation. Basenjis are one of the geniuses of the dog world. Without enough mental stimulation and walks they can become bored, which can lead to aggression / frustration.
If there is someone else with basenjis in your area, they might be able to help. I doubt most trainers / behaviorist would help to be honest. Also, walking the dog for at least 3-5 miles a day over three or four walks and keeping a good structure to the day might solve the problems.