To reproduce:
1) Open attached project and scene
2) Build a standalone player (tested on all three)
3) Run it normally

Expected: No leaking, the memory normalizes after a few seconds of running.

4) Run it with -batchmode argument

Actual: A massive memory leak can be seen (speed depends on the version, with newer versions leaking faster, but the slowest was still roughly a gigabyte every 5 seconds)

Reproduced in 2017.4.0f1, 2018.1.0f1, 2018.2.13f1, 2019.1.0a6