BGP Routing not working as expected

Hi together, I’m pretty new to BGP and vyos.
My BGP Setup is as follows:
set interfaces ethernet eth0 address ''
set interfaces ethernet eth1 address '2001:7f8:f2:xx:x:axxx:xxxx:1/64'
set protocols bgp 21xxxx address-family ipv6-unicast network 2a0e:b107:xx::/48
set protocols bgp 21xxxx neighbor 2001:7f8:f2:e1::xxxx:1 remote-as '20xxxx'
set protocols bgp 21xxxx neighbor 2001:7f8:f2:e1::xxxx:1 update-source '2001:7f8:f2:xx:x:axxx:xxxx:1/64'
set protocols static route6 2a0e:b107:xx::/48 blackhole distance '254'

This setup works as long as i do not try to use one of my announced IPs from my range 2a0e:b107:xx::/48 on a new interface like eth2.
set interfaces ethernet eth2 address '2a0e:b107:xx:1::1/64'

Right after setting this address BGP stopps working and trying to ping the neighbor 2001:7f8:f2:e1::xxxx:1 also fails. Traceroute shows that the route is now trying to go via the new eth2.

For first you use an incorrect update source address.
You need to declare update-source without netmask.

You should have gotten errors with your commit.

vyos@r1# commit
[ protocols bgp 65001 ]
% Invalid update-source, remove prefix length 
Error configuring routing subsystem.  See log for more detailed information

Can you use these (2001:DB8::/32 or /64) address space for providing configuration?

It is no clear what there

For example network range for 2001:db8:f2:aa:a:aaaa:aaaa:1/64


Without full configuration and understanding IP scheme I can’t reproduce it.

vyos@r1:~$ show interfaces 
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface        IP Address                        S/L  Description
---------        ----------                        ---  -----------
eth0             -                                 u/u  
eth1             2001:db8:f2:aa:a:aaaa:aaaa:1/64   u/u  
eth2             2a0e:b107:bb:1::1/64              u/u  

vyos@r1:~$ show ipv6 bgp neighbors 2001:db8:f2:aa:a:aaaa:bbbb:1 advertised-routes
BGP table version is 1, local router ID is, vrf id 0
Default local pref 100, local AS 65001
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 2a0e:b107:bb::/48
                    ::                       0         32768 i