A referral is not the same as a second opinion, and this difference matters for claims.
In Malaysia, true veterinary specialists are not common in the same way they may exist in some other countries. In practice, if your vet refers your pet to another clinic, it is usually because the first clinic does not have the equipment, facility, or experience needed for that particular illness or treatment.
That is generally treated as a referral, not a second opinion. Based on claims handled so far, referral treatment has generally been accepted where the claim is otherwise covered and supported by the usual documents.
A second opinion means you choose to see another doctor or clinic to get an alternative diagnosis or treatment view, rather than being referred because the first clinic could not manage the case. That is different from a referral.
If this position changes in the future, the policy terms and conditions will apply. To avoid confusion, ask your vet to note the referral clearly in your records or invoice when another clinic visit is needed.