ConstructUnion runs out of memory

I create a geometry bag and added 40k or so polygon features into it using the geometry collection interface. All-together, adding geometries brings my memory stamp up to roughly 520MB or so. After this, I create an empty polygon and use the topological operator to ConstructUnion against this geometry bag. This operation spins for 20 seconds or so, then the memory stamp increases without bound, crashing my process.

I originally modified my code to use ConstructUnion instead of multiple Unions, since I saw a noticable performance increase. Unfortunately, it looks like construct union has some type of sporaddic memory leak.

Questions and comments welcome!