I am finally able to confirm the problem.

The problem occurs only when connecting to oracle using the script task using the code below. If I connect using an Oracle provider it works fine

Dim cnn As OleDb.OleDbConnection

Dim sConnString As String = Dts.Variables("User::OracleConnectionString").Value.ToString

cnn = New OleDbConnection(sConnString)

Dim cmd As New OleDbCommand

With cmd

.CommandType = CommandType.Text

.CommandText = "SELECT dw_info.get_status(TRUNC(SYSDATE)) STATUS FROM DUAL"

.CommandTimeout = 0

.Connection = cnn

End With

cnn.Open()