IF formula for timestamp

[JaneDoe2205]

I am using the above formula for time stamps to automatically be input if data is entered in the specified cell. However, whenever I enter data in the g7 column, the time and date stamp changes for each item in the b column in unison. Not just changing the time and date for b7. I do not understand why the formula is not working. 

[#2]

@JaneDoe2205 

Do B8, B9 etc. contain formulas?

If so, what do they look like?

[#3]

Yes, the formulas are:
=IF(G8<>"", IF(B8="",NOW(), B8),"")
=IF(G9<>"", IF(B9="",NOW(), B9),"")

[#4]

@JaneDoe2205 

Did you enable Iterative Calculation in File > Options > Formulas? That is required for these formulas to work.

[#5]

Yes, I did. @HansVogelaar 

[#6]

@JaneDoe2205 

I have attached a small sample workbook. What do you see if you enter or edit a value in column G?