My POV is that just because the errors went away, does not mean that you solved the problem. The HTTP protocol give a synchronous response. So, if you are reaching a threshold, whether it be a capacity limitation, or a business agreement threshold, the HTTP response code will be the indication. With Sumo Logic, if you are over exceeding your bursting rate limits, we will return a 429 response code. Heroku Logplex is not tuned for negative response codes, and will drop data. With a syslog endpoint, you may be losing data as well, except that syslog does not have a response channel, so its only option is to drop the data. For Sumo Logic, you will see notifications in the Audit Log indicating that throttling is being applied. When this happens you should contact support, or your account team, to either make adjustments to your limits, or increase your plan.