I have contacted both OCBC and SGX.
The short answer is that the counter is listed in the primary currency, in this case EUR.
The longer answer is from SGX,
"Please note that in the CDP statement, the market value of the listed security with dual currency trading functionality will be computed based on the last done price of the Primary Currency counter and the total number of unit holdings of the listed security.
For this instance, the primary currency for Cromwell European REIT is in EUR and hence it was reflected as EUR in your CDP shareholdings.
You may refer to the following link for more information regarding Dual Currency Trading:
I try to learn something new everyday…