When I see ‘error’ or ‘offset’ in any post dealing with a date or datetime value, my initial assumption is that the poster is receiving a response that shows either the date off by a day or the time off by a number of hours from what he or she expects. Even more irritatingly, in the first instance the problem may not seem reproducible at first or may suddenly disappear during testing. If that is the case here, I suggest you check the current value of the ‘Use the same time zone (GMT) for all collaborators’ configuration toggle for {Premiere - HKT}. If it’s enabled, the response will be off by however many hours your local time zone is offset from UMT.
If you’re receiving a different sort of error — or receiving an #ERROR! message as the result — it might be caused by the evaluation of a date field with an empty string. (In most cases, Airtable will accept a null string — ‘""’ — as interchangeable with a BLANK() field, but not always.) If so, you can modify your formula to read
IF({Premiere - HKT}=BLANK(),'N/A',DATETIME_FORMAT({Premiere - HKT},'dddd'))
or, even better [as a habit, because it bypasses any potential oddity regarding how "", 0, and BLANK() are evaluated], invert the logic of your IF() statement to take advantage of Airtable’s implicit understanding of null and non-null values:
IF({Premiere - HKT},DATETIME_FORMAT({Premiere - HKT},'dddd'),'N/A')
If your trouble is something other than either of these, give us a little more information, and we’ll back up and run it over again.
