Hi,
Your company code currency is USD and your vendor currency is SGD.
If the GR document, the GR/IR clearing account is 1009.30 SGD(Cr) and during IR document, the GR/IR clearing account should be 1009.30 SGD(Dr). If you view the accounting document in IR where you can see the difference with local currency(USD) posted to G/L account which is there in PO as result of exchange rate difference.
Can you share accounting entries with Local currency and Transaction currency for your PO
1. Goods receipt account document
2. Invoice receipt account document
Regards,
Biju K