Update Lookup Column with Multiple values using Designer Workflow in SPO

Using a 2010 workflow type and updating the Lookup column in 1;#;#2;#;#3 format resolved the issue.Looks like this is a bug in 2013 workflow type.

Update: In SharePoint Designer 2013 workflow,to update a Lookup column, you need to update the ID value of the looked up column,there are no formats to update Lookup column.Have to check if this works for Multi-select Lookup Column

In the below example, SOW# is a Lookup column and its updated using the ID columnenter image description here