This is an unusual case of the adjective not deriving from the past participle, where the action leads to the state. Normally, the words are the same:
"We painted the door - The door is painted."
"I washed the dog - The dog is washed."
"They've eaten the food. The food is eaten" etc
But this is not invariable:
"Such agreements are unlikely to be legal/legalised under Article 81(3). - Different meanings. legalised (p.p.)-> legal (adj)
"The door will not be open/opened during the concert." opened (p.p.)-> open (adj)