Problem with Communications 0 Days After a Subscription is Paid

Hello. I just upgraded to Membership 3.5.1.2. I have a Serial subscription set to renew automatically each day (I am doing this for testing purposes.)

I am experiencing an issue with the Communications feature.

I have a few Communications set up. One of them is a welcome message I sent to new subscribers once they make a purchase. I have the communication set to "0 Days After a Subscription is Paid."

My first issue is that I didn't receive the Communication until a an entire day after I purchased my membership. Before I upgraded, I used to get the welcome email within 5 minutes. After this latest upgrade it takes almost an entire day.

My second issue is that after I cancel my membership, I keep getting the welcome email once every few days. I never received the welcome email after I cancelled the membership. But after the upgrade, it comes even after I cancel. I thought it was only supposed to come once?

Thank you for your help.