The legacy MRP was able to firm batch orders created out as a result of "plan planning formula" process, which can be found from the planned orders page. With Planning optimization this is not supported. This idea is for bringing this process back into planning optimization, since the product team has said the following on the LCS issue 1034725: "Upon further investigation, we have determined that while this is a bug, it doesn’t meet the level required for us to fix at this time."

Full text on: https://fix.lcs.dynamics.com/Issue/Details?bugId=1034725&dbType=3&qc=d2e4a8d6385349223618c136a8fc1724e2709a374db90ced558608bee9bcf5c8