I called BMO this morning to find out why my RPL dividend was not posted in any of my accounts on May 15th. The rep didn't know but got back to me within 15 minutes. He was very nice but still clearly didn't have a clue and probably just relayed what his supervisor told him to say, which was: "There was a processing problem in our back office. They are way behind in processing but the dividend is in your account right now and the money is available to you, even though it may not be posted to your account until late this evening or Tuesday morning."
Anyway... if you're an Investorline customer (according to Lester at BMO) your RPL div cash is in your account, even though it may not have shown up yet.