Cart rule. Presta dont find some customers in field "Limit to a single customer"

[larrson]

Hello,

i have a issue with the cart rule. When it's come to the field "Limit to a single customer", the names of the matching clients are displayed as soon as the first letters are typed. Unfortunately, my shop don't find all of the clients i'm looking for. For whatever reason, there are customers he can't get. I tried to find the difference between the ones he finds and the ones he doesn't, but i can't figure out.

Some ideas anyone ?
Thank you for reading.

Prestashop 1.7.6.5