Oblivion Sower is currently broken, probably since the last update, since it used to work fine before.
When it enters the battlefield it is supposed to Ingest 10 and Process 5. However, currently it seems to actually just convert (ingest>process?) a handful of gems to the PW, leaving no leftover void gems. In fact, I’m not even sure it’s quite 5 gems converted, the couple times I’ve tested it so far it’s seemed more like 3-4.