Hi Sanjeev,
Could you please also show me your text mapping customizing in spro "Text Mapping for Inbound and Outbound Texts" for PO, that is between BUS2012 and SUPO?
In addition, please change the field "Changable" in your text schema to "Cannot be changed" for "Message from purchaser" of SUPO.
For the SUS purchase order, all texts from purchaser to supplier are not changeable, by none of the users. These are display only texts and the customizing should be set accordingly.
Please let me know if this helps.
Best regards,
Wendy