Replicated the code and notice that the issue is replicable:
The Last day becomes N/A for March 29, 2004, when we adjust the end date to March 30,2004 then the 29 has value and the N/A moves to the day 30.
Here is the code try changing the End date into march 29, 2004 then 30 and then 31
import refinitiv.data as rd
rd.open_session()
df = rd.get_data(
universe = ['AAPL.O'],
fields = ['TR.CLOSEPrice', 'TR.LOWPrice', 'TR.CLOSEPRICE.DATE', 'TR.Volume.Date', 'TR.VOLUME', 'TR.NUMBERBLOCKTRADES', 'TR.TSVWAP'],
parameters = {'SDate': '2004-03-25', 'Edate': '2004-03-31'}
)
display(df)