Both occurred on the same day but both did not occur the same time on the same day. If both occurred the same time on the same day then that would call for the present tense participle as you say. However, it is Aorist participle because it is a prior action to the appearance but both on the same day.
GE:
NOTHING in or about or of the Aorist guarantees or demands or even SUGGESTS the time-expiry-limit "on the same day", Dr Walter. Jesus eight days later appeared this VERY SAME 'ANASTAS'- "The Risen One" of Mk16:9; and for forty days, this VERY SAME 'ANASTAS'- "The Risen One" of Mk16:9; and ascended into the air this VERY SAME 'ANASTAS'- "The Risen One" of Mk16:9.