Hi,
On posting MIRO with subsequent debit/credit, system will post to respective G/L accounts for additional entry for correction by business needs on vendor invoicing . If you do want those entries, then better go for posting invoice/credit memo in FB60 for your vendor or post MIRO with entering G/L account by activating G/L account TAB in MIRO. refer
Unplanned cost to be captured while doing at MIRO
Regard
Biju K