Memory leak when importing fbx with GI enabled and static lighting disabled? 4.25

I have a 100mb fbx file that I import into a tiled outdoor ray tracing enabled world map. However since interiors are oddly lit I disable static lighting. During subsequent imports of the 100mb fbx file UE rapidly fills all my ram (32gb) and causes the computer to stutter, importation progress is minimal and often it causes various parts of the OS to crash / reset. Reenabling static lighting fixes the issue, so for now I enable it whenever I need to update large mesh files. Is this a bug in 4.25?

My system is an 8700k i7, 1080 gtx, 32gb ram and running from a samsung sata ssd.