UNIQUE FILTER formula automatically getting converted into an Array formula in O365

In the attached Excel, I have a formula (tab SUMMARY, E6) which is a UNIQUE, FILTER one.

=IF(C5=0,"No Feedback Available",(IF(B3="Weekly Summary",(UNIQUE(FILTER('WEEKLY DETAILS'!G3:G9999,'WEEKLY DETAILS'!D3:D9999<>""))),(UNIQUE(FILTER('MONTHLY DETAILS'!G3:G9999,'MONTHLY DETAILS'!D3:D9999<>""))))))

I have uploaded the Excel on AWS so it can be used by a program that writes value in the 1st and 2nd tab of the Excel.
When I am downloading the report which is generated after the program writes data into it, the formula in the cell E6 is appearing with curly braces in the beginning and at the end, like the following:

{=IF(C5=0,"No Feedback Available",(IF(B3="Weekly Summary",(UNIQUE(FILTER('WEEKLY DETAILS'!G3:G9999,'WEEKLY DETAILS'!D3:D9999<>""))),(UNIQUE(FILTER('MONTHLY DETAILS'!G3:G9999,'MONTHLY DETAILS'!D3:D9999<>""))))))}

Due to Array formula, only the first unique value is appearing in the result, an

Any ideas on how can I prevent my formula from being automatically converted into an Array formula? Thank you for your guidance in advance.

There is a thread for the same issue on Microsoft Answers but us locked and unresolved: answers.microsoft.com/en-us/msoffice/forum/all/automatic-change-of-regular-formulas-to-array/4fb2d834-7f7c-4b21-bb43-690fb5ba244c

Hi Pepe,

Applying 'At' symbol does not seem to work. I am getting only the first value after adding the symbol. Please see the file attached