Add to cart not working when title includes “Rolex”

Dear forum,
we have the following problem:

In the shop of one of my friends (WordPress and plugins all updated to the latest versions) it is not possible to add a product to the cart, when the title or permalink includes the word “Rolex”.

When the title includes it, it’s impossible to add it from any source (“recently added” widget, shop, product page) and when the title doesn’t include it, but the permalink does, it’s still not possible to add it to the cart, at least from the single product page.

Right now I have changed the spelling of the word “Rolex” to using a capital “i” instead of the lowercase “L” but that’s not a real solution, it just makes it work for now. I have left the normal and correct spelling in the following product for reference:
/product/rolex-datejust-36-buckley-dial-1603-jubilee-1970/

If the word includes a space (“Ro lex”, “Rol ex”) it all works normally, just the word “Rolex” seems to cause problems. It’s such an odd issue, because it’s really just this single word that seems to be the problem, all other brands work fine, the rest of the title seems to be completely irrelevant. However, maybe that’s also one thing to go off of to find a solution.

I hope someone here has an idea or had a similar issue in the past that could lead to the solution.

Thanks in advance for all answers and ideas!

Best
Niklas

The page I need help with: [log in to see the link]