onEdit(e) Trigger(Both simple and Installable) will not trigger unless a human explicitly edits the file. In your case, Your seem to be getting value from an external source (specifically, Google finance data).
Also, for Google finance data,
Notes:
Having said that,
-
In cases where the change is made by a formula(like
=IF()
,=VLOOKUP()
) other than auto-change formulas(like=GOOGLEFINANCE
,=IMPORTRANGE
,=IMPORTXML
, etc), Usually a human would need to edit some other cell- In which case, You will be able to capture that event(Which caused a human edit) and make changes to the formula cell instead. -
In cases where the change is done from sheets api, a installed onChange trigger may be able to capture the event.