Model() is not replacing the old value within a transaction

[alkuma]

GORM Playground Link

#739

Description

Attempt to insert into two different tables within a transaction one by one.

Expected : Successful commit should lead to a record each in both the tables.

Actual : the transaction errors with the error described in the PR description

[alkuma]

The tests for this #739 are impacted by the same issue that's reported in #730

[xuyang2]

#739 (comment)