linux running a script on a mounted fritz-Box share result in "bad interpreter" in ubuntu 22.04, works on 18.04 (other shares work)

A script like:

#!/usr/bin/env bash...or#!/usr/bin/env python3...

will result in (german):

-bash: /mnt/Fritz-USB/FritzUSB/t.sh: /usr/bin/env: Defekter Interpreter: Eingabe-/Ausgabefehler

translated:

-bash: /mnt/Fritz-USB/FritzUSB/t.sh: /usr/bin/env: Bad Interpreter: I/O-Error

This only happens on a PC running ubuntu 22.04 on a PC running ubuntu 18.04 everything works as expected.It happens (on 22.04) with every (valid) shebang!

The Mounting options are equal on both systems (except closetimeo=1, which is not available on 18.04).

On ubuntu 22.04 the script will work if started as (or similar):

bash /mnt/Fritz-USB/FritzUSB/t.sh

If I copy the script onto another mount it will work:

cp /mnt/Fritz-USB/FritzUSB/t.sh /mnt/NAS/t.sh/mnt/NAS/t.sh <-no error

I searched the web, but had no luck. maybe someone here has an idea.

Thanks