Dear @Gunner, as far as I have seen in my case at least, the problem is related to external sites like ThingSpeak. In my project I have a virtual switch in the Blynk that activate or de-activete the ThingSpaek sending data. With this active, the memory leakage is just awful in contrary with this de-activated the memory leakage is gone…
If you have time and want to test, do the same and make a timer printing for the free.heap and let us know the result.
terminal.printf("ESP free heap=%d, time:%02d:%02d:%02d\n", ESP.getFreeHeap(), hour(), minute(), second() );