Yes, previous encumberments can be cleared from property history, if the person takes steps to get rid of the encumberments. If a person has access rights, perhaps they will transfer the rights back. If a person has a mortgage, they can pay it off. Encumberments can go away with some legal action.
I think that previous encumberments can be cleared from property history. I think that when a property is cleared of such issues like liabilities, leans, and debts, then such problems like encumberments can be take cared of. I also think that buyers will not care too much as long as their investment is safe.
I believe previous encumberments can be cleared from a properties history. I know of one case where a person built an addition onto the neighboring property owners land. The house was sold without divulging this information and the problem was handled by the next property owner who agreed to buy the sliver of land the addition was on. Things can be fixed and cleared up, but it usually takes a lawyer.
History exists and it is factual. A property's history is just that; facts pertaining to a property. If there have been previous problems, whether or not they have been remedied, it should be noted in the property's history so that any prospective purchaser or purchasers in the future can see a summary of past inefficiencies, damages, or other negative or positive influences that exist concerning the property.