Hi @A_x_e_l 

For us to have more info, post screenshots with how your Zap steps are outlined and configured in EDIT mode.

Hi @Troy Tessalone 
Thank you for your contact. I am attaching the images in order of the entire automation and of each specific item.

@A_x_e_l 

There seems to be a discrepancy in the screenshots with the Looping step.

Confirm which Looping action is being used. (Text or Numbers)

NOTE: You probably want to add a Filter after the Step 3 and before the Looping step to make sure there are values to loop.

Yes, it was my mistake; the looping is done with Number. The problem is that it finds everything, but when it comes to modifying the status in Salesforce, sometimes it changes 7 out of 10 records, other times it changes 5 out of 10, sometimes 6 out of 10, with no apparent logic.
I could add a filter before and after the looping, but I don't think that's the issue.

@A_x_e_l 

Try this…

Use this Zap action for Looping: Create Loop from Line Items

For the Record IDs found in Step 2, pass those into the loop to iterate.

Then remove Zap step 4 (Find Record).

Instead, map the Record ID from the Looping step to the Update Record step.

That way each record found in step 2 is updated.

I could add a filter before and after the looping, but I don't think that's the issue.

This feedback is to prevent possible Zap Run errors.

Yessss, oh my god!!! Thank you so much! The Find ID actions were overlapping. Thank you so much! It works!