Tick checkbox for timestamp in google sheet

I'm creating a request/problem form in google form and responses are viewable and editable in google sheet. In the google sheet, I would like to have a timestamp checkbox for myself to whenever I'm done with the problem.

It is look like this

...

Also, This is the function I put in column K(the timestamp) and the column J is the checkbox column.

=ArrayFormula(IF(ROW(K:K)=1,"DATE",IF(ISBLANK(K:K),"DATE",IF(J:J = true,IF(K:K<>"",K:K,NOW()),""))))

The column K function in sheet

The function for column K work as intended and I just need to manually add the checkbox in column J which is fine enough.

But, the problem is happen when a new form is submitted and update the google sheet. Error message appear " "array result was not expanded because it would overwrite data in K81."

The problem

My objective as I mention above is to have a timestamp checkbox for each problem submitted by google form. Is there are any way to work around this?