There is a difference between using human tissue in the development and using it in production. If it was necessary for production, a constant stream of human cell material would be necessary. Read about it here:

The virus needs to be reproduced to create the vaccines listed on the previous link.

Each vaccine was developed from human fetal cells, in order to develop the vaccine manufacturing process.

This manufacturing process requires process validation, and validation if the raw materials to demonstrate reliable/on-going manufacturability.

They need to continue using human cells to culture the virus, and if they didn't, then they'd declare what cellular material was used as a substitute. They would love to distance themselves from the use of fetal tissue, so this is a no brainier.

The human cells may be mostly filtered out of the vaccine.

However, there's no possibility of removing 100% of the human proteins, etc.

These process byproducts will remain in the vaccine solution as contaminants.