I created this DDL to vet out your code and I do not see any issues with the above code you provided.
The issue seems to be elsewhere . And your code is doing an update of a table row with the same values of the table row, why? Is this some sort of learning you are doing?
use sqlteam
go
declare @HoldPatientID int = 999;
create table #tblDimPatients(PatientID int ,
FullName nvarchar(50),
FirstName nvarchar(50),
MInitial nvarchar(50),
LastName nvarchar(50),
Suffix int,
Address1 nvarchar(50),
Address2 nvarchar(50),
City nvarchar(50),
State nvarchar(50),
ZipCode nvarchar(50),
County nvarchar(50),
PhoneHome nvarchar(50),
PhoneWork nvarchar(50),
PhoneCell nvarchar(50),
Fax nvarchar(50),
Email nvarchar(50),
DOB nvarchar(50),
Gender nvarchar(50),
VocEdCoordinatorID nvarchar(50),
GraduatingYear nvarchar(50),
Comments nvarchar(50),
Status nvarchar(50),
HomeSchool nvarchar(50),
CurrentSchool nvarchar(50),
MedicalRecordNumber nvarchar(50))
UPDATE #tblDimPatients
SET FullName = FirstName + ' ' + MInitial + ' ' + LastName,
FirstName = FirstName,
MInitial = MInitial,
LastName = LastName,
Suffix = Suffix,
Address1 = Address1,
Address2 = Address2,
City = City,
State = State,
ZipCode = ZipCode,
County = County,
PhoneHome = PhoneHome,
PhoneWork = PhoneWork,
PhoneCell = PhoneCell,
Fax = Fax,
Email = Email,
DOB = DOB,
Gender = Gender,
VocEdCoordinatorID = VocEdCoordinatorID,
GraduatingYear = GraduatingYear,
Comments = Comments,
Status = Status,
HomeSchool = HomeSchool,
CurrentSchool = CurrentSchool,
MedicalRecordNumber = MedicalRecordNumber
WHERE (PatientID = @HoldPatientID)
drop table #tblDimPatients