I work for an ISV and we recently received some reports from customers of the same error.
We've narrowed it down to the following:
This only affects those who've have had a Salesforce IQ application installed in their Org. Uninstalling alone doesn't resolve the problem.
This only occurs in Spring 20 pre-release sandboxes. We've seen this specifically in ...
I'm posting as an answer. There are couple of issues with your code.
Email Template query is returning more than 1 record however you're
storing it in a single instance.
SOQL's written in for loop.
For temporary fix, get the list of Email Template and then use the  index record. Refer below code for reference:
global void execute(Database....
This may have been included in the code you didn't post, but both rRecord and rpRecord are of type list<Renewal__c>. It would seem to me that if you use Limit 1 on both of those queries, they can just be Renwal__c records and won't need to be lists. Otherwise, your code will need to get the values of rRecord and rpRecord which could possibly be ...