On both sites, unless you need some kind of ‘hairpin nat’, remove from nat your internal interface (ETH00), inSiteA the 2nd entry visible in postrouting
9167 821K MASQUERADE all -- * ETH00 0.0.0.0/0 0.0.0.0/0
2nd entry in SiteB as well
3514K 235M MASQUERADE all -- * ETH00 0.0.0.0/0 0.0.0.0/0
These entries translate the source ip addresses of outgoing packets with the ip addresses of these interfaces.
Also, if you need that your link be Layer 3 transparent, remove also, in SiteA, from NAT enabled interfaces, the VPN00.