I have a strange problem that i cannot figure out why this is happening?

On my CMS side i have a Page Type called Segment
It has a property that points to a Catalog Category
The "name in the URL" property is set to Enduro on the Segment page

The Category in the Commerce has also the same "name in URL".

I have multiple of this segment/Catalog pages. I have only problem with this one, called Enduro.

For Czech language i have altered the Web address prefix to cz.

The Czech language has a fallback to English.

Now, if i clone the Enduro Segment page, it will get "name in Url" = enduro2

If i go to domain/cz/enduro2, everything work tip top.
if i go to domain/cz/enduro, i get 404???

if i go to domain/cs/endoro, Works
if i go to domain/cs-CZ/endoro, Works

Futhermore, when looking/debuging in the code (Episerver.dll)

in public virtual IRouteHandler GetRouteHandler(RequestContext requestContext)

the language past in is [en] for cs and cs-cz
but for cz language i get cs-CZ.
It seems like somewhere in the code there is a error. It seems like the fallback does not work for what ever reason?
And so far i know i only have the problem with "name in URL" Enduro

Any suggestions on how to debug this and get some more info why this is happening?