Landscape easement / Entrance signage

Hello all!
Our community entrance has a small brick monument with little landscape. The easement for the monument is 30’x30’ and has electric. The homeowner whom owns the front property gets very upset when the HOA wants to use the easement, such as for decorations or even landscape maintenance. I have been verbally reprimanded for being on the easement and not letting the homeowner know ahead of time. Also the homeowner has turned the power off at the box for the lighting because the smaller landscape lights are aiming too low? They have stated it’s their property multiple times. I am always very patient and try to be polite, but it seems to go no where. Does anyone have advise for how to handle this situation? The subdivision is only 3 years old and I am new to the board. I have already reached out to the management company for legal advise which I am awaiting. I have also just phoned a company about a survey to visually mark where the easement is. ( this is because I am afraid the developer has actually placed the monument passed the easement)

Thanks!

What does your governing documents say? Pay Close attention to the plats. Typically your CC&R's will clearly state all easements, especially if the HOA provides landscaping or snow removal.. Covenants will clearly state that the HOA, The BOD or their agents can come on the property without advance notification ,i.e, cut grass, take a picture for compliance issues. If you are in a condo there are different rules for entering the unit itself.