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Before the opportunity is 'closed won', the opportunity type field is shown as 'renewal'. And the field 'subscription id' will also mention the subscription id of the subscription for whom renewal is being made. After the actual subscription creation is done and the stage is 'closed won' on the opportunity, the 'CB subscription id' field is populated with the subscription ID. This is an expected behavior where after actual subscription creation is done and the stage is 'closed won' the 'Cb subscription id' field will be populated with the value but initially the 'subscription id' field would only show you for which subscription the renewal is being made.
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