a2.NumericValue check distinct values for this column,
you might have anything other than numeric values.
or add , and a2.NumericValue like '%[0-9]%'
like below.
Select top 1 a2.numericvalue
from dbo.ctc_mde_valueaudit a2
where a2.UTagId = mva.UTagId
--And mva.id > a2.Id
and a2.NumericValue is not null
and a2.NumericValue like '%[0-9]%'
/*and a2.NumericValue is not null and a2.NumericValue != 0
and mva.NumericValue is not null and mva.NumericValue != 0*/
order by a2.id desc