Please see Renon's answer above.
To further elaborate on the issue, you can search your database for other affected rules. First, get the current staging version for your site:
SELECT * FROM `flag` WHERE `flag_code` = 'staging';
You will see something like this:
Next, take that timestamp, and inject it into this query:
SELECT rule_id, GROUP_CONCAT(`row_id`)
WHERE(created_in <= '1595433660')
AND (updated_in > '1595433660')
GROUP BY `rule_id` HAVING COUNT(*) > 1
This will return the
row_id of affected Sales Rules. Update those rows using Renon's method so that only one row for each rule matches the above date conditions, and you should no longer have this problem.
Note: I observed this issue on Magento 2.3.5-p1