Validation not working as expected after changing the field name

Hi Appian team,

I have changed the display name for CDT and there for modified the field name in interface as well. I have done the below code change, but the regular expression added for validation is not working as expected.

Can anyone help me out to solve this issue?

below is the code snippet used.

a!textField(
label: "Purchase order (PO)/Sales order (SO)/STO/Requisition",
labelPosition: "ABOVE",
value: trim(
index(
ri!PF_Request,
"Order_Del_Number",
null
)
),
saveInto: {
a!save(
ri!PF_Request.Order_Del_Number,
/*if(ri!PF_Request.GBEID=18,*/
/*left(*/
/*trim(*/
/*save!value*/
/*),10),*/
/*trim(*/
/*save!value*/
/*))*/
trim(save!value)
)
},
required: true,
validations:if(ri!PF_Request.GBEID = 18, if(regexmatch("^([0-9]{1,10})$",ri!PF_Request.Order_Del_Number),null,"The number provided should not contain any special character and can have upto 10 digits"), null )


)

Also please see the below discuss link to understand what are the changes I have made.

Thanks

Sunu Sam

https://community.appian.com/discussions/f/process/22377/how-can-i-just-give-a-display-name-to-columns-in-cdt-which-has-a-different-name-in-database-tables-also-i-have-more-questions-regarding-appian-features/87736#87736