Loan compression is when you are only eligible for a single 500k property (500k for example) but u submitted two or three or even 10 property. 10 property means 500k x 10 = 5M loan compressed using your 500k eligibility.

A safe loan compression is when you can afford to pay, let say you are eligible for a 500k property but you buy a 300k property with a 200k property. Actually this one is not really compressed lah, we call it multi submission, we do this to avoid 70% margin for the 3rd property, or for your case want to take advantage as a first home buyer - can waive stamp duty or take Skim Rumah Pertamaku got 100% margin.

A risky one is when you buy beyond your affordability. Get ready kena lelong.

Ok. If thats the case, presuming both property submitted to the same bank:
If only eligible for either one, then the banker will ask which unit u want and which to cancel. Booking for canceled unit will be returned. If cancel both unit, booking for both will burn.

If each unit submit to same or different bank:
Either bank may approve or reject. If both bank approve, then you have to take both unit. If want to cancel any or both unit, the booking for the canceled unit will burn.