SNMP/UDP uRPF trouble

hello i have some trouble with SNMP, i have many mikrotik… differents hardware and software. but the problem is everywhere.
The router has two ression (OSPF/BGP don’t matter) - public IP announced to peer A, privat IP to peer B, dafault from peer A.

SNMP not responding when requesting privat IP, no problem with TCP/ICMP.
no firewall

ip setting print
ip-forward: yes
send-redirects: yes
accept-source-route: yes
accept-redirects: yes
secure-redirects: yes
rp-filter: no
tcp-syncookies: no
max-neighbor-entries: 8192
arp-timeout: 30s
icmp-rate-limit: 10
icmp-rate-mask: 0x1818
route-cache: yes
allow-fast-path: yes
ipv4-fast-path-active: yes
ipv4-fast-path-packets: 0
ipv4-fast-path-bytes: 0
ipv4-fasttrack-active: no
ipv4-fasttrack-packets: 0
ipv4-fasttrack-bytes: 0