Can you reproduce this issue in a clean project?
I made a new project with first person template, add a new actor blueprint (just created. opened bp editor but no edits) and tested again and it reproduced.
Editor ui component also seems to trigger part of these. (as just mouse over, selecting a component, show tool tip, scroll in detail tab etc also cause memory usage up. Some of them seems to be cleaned but total memory usage goes up.)
Environment:
OS: Windows 7 64bit (Japanese)
Ram: 16GB
UE: 4.15.2
UE Language setting: Step 1-19: Japanese, Step 20-22: English
BTW, attachment file link seems something wrong.
