Information
By default, the IPsec replay window on the IPsec tunnel is 512 bytes.
See https://www.cisco.com/c/en/us/td/docs/routers/sdwan/configuration/security/vedge-20-x/security-book/config-sec-param.html for more information.
Solution
You can set the replay window size to 64, 128, 256, 512, 1024, 2048, or 4096 packets:
vEdge(config-interface-ipsecnumber)# ipsec
vEdge(config-ipsec)# replay-window number