Weird bug on calculated column for a lookup

Hi Community,

Context : I use SP 2013 Standard. I have 2 lists on my site. I created a lookup from  list_A to list_B, but as I want only the active items of list_A, I created a calculated column [Active Item] with =IF([Status]="Active";[Title];"")

I've done that many times already, and it always worked great.

Bug : When I update any value in an item from list_A, my calculated column is updated, and the result showing is -214428456 !!  (see screenshot below)

The first 2 lines suffer the bug, the next 4 are correctly calculated (but have NOT been modified since the [Active Item] column was created, the last 1 is active)

NB : If I go to list settings, open the [Active Item] column and save without changing anything, the inactive item are calculated back to the <blank> value.

Does anybody seen that already ?

Thanks for help !