AWS RDS update failing after restore from snapshot - amazon-web-services

Question

i created a RDS in AWS through serverless.
First it is don't have encryption so i took a manual snapshot of rds instance and created encrypted snapshot from that.
Now in serverless i changed like below.
1. i removed rds instance from aws stack (added a condition on RDS instance and re-design the template without rds)
2. Now i am re-deploying data base with DBSnapshotIdentifier.
3. Now if i try to re-run the stack with out DBSnapshotIdentifier it is failing.
Here my question is, Once if we use DBSnapshotIdentifier every time we need to provide that?
Note : i created a fresh stack with out providing DBSnapshotIdentifier created fine.
i re-run the deployment with out providing DBSnapshotIdentifier it's working.
The above case also similar i guess.
Please go through below yaml you will understand what i did on rds
createRDSInstance : it is used to create or remove rds from template.(from stack)
dbSnapshot: it is used to the way of deployement snapshot or simple update
testCrid:
Type: "AWS::RDS::DBInstance"
DependsOn: "testVPC"
Condition: createRDSInstance
Properties:
DBInstanceIdentifier: "Crid-${self:custom.arguments.stage}"
DBName:
Fn::If: [ dbSnapshot, "${self:custom.arguments.database}", Ref: "AWS::NoValue" ]
Engine: "MySQL"
EngineVersion: "5.7.16"
DBInstanceClass: ${self:custom.arguments.dbInstanceClass}
MasterUsername: test
MasterUserPassword: ${self:custom.arguments.password}
PubliclyAccessible: ${self:custom.arguments.public}
DBParameterGroupName:
Ref: "CridParameterGroup"
VPCSecurityGroups:
- Ref: "PrivateSubnetDBSecurityGroup"
DBSubnetGroupName:
Ref: "CridSubnetGroup"
AllocatedStorage: '5'
StorageType: "gp2"
StorageEncrypted: true
MultiAZ: true
DBSnapshotIdentifier:
Fn::If: [ dbSnapshot, Ref: "AWS::NoValue","${self:custom.arguments.dBSnapshotIdentifier}"]