Route Problem ?

This is tcpdump from F5, you can see that the F5 don't send any packet to portal server (z.z.z.z)

my pc= x.x.x.x virtual server= y.y.y.y portal = z.z.z.z

09:59:49.362662 IP y.y.y.y.https > x.x.x.x.62282: F 134:134(0) ack 307 win 4685 09:59:49.363621 IP x.x.x.x.62282 > y.y.y.y.https: . ack 135 win 64107 09:59:49.368338 IP x.x.x.x.62284 > y.y.y.y.https: S 630490270:630490270(0) win 8192 09:59:49.368365 IP y.y.y.y.https > x.x.x.x.62284: S 471673062:471673062(0) ack 630490271 win 4380 09:59:49.369037 IP x.x.x.x.62284 > y.y.y.y.https: . ack 1 win 64240 09:59:49.371707 IP x.x.x.x.62284 > y.y.y.y.https: P 1:259(258) ack 1 win 64240 09:59:49.371730 IP y.y.y.y.https > x.x.x.x.62284: . ack 259 win 4638 09:59:49.372757 IP y.y.y.y.https > x.x.x.x.62284: P 1:134(133) ack 259 win 4638 09:59:49.378836 IP x.x.x.x.62284 > y.y.y.y.https: P 259:306(47) ack 134 win 64107 09:59:49.378840 IP x.x.x.x.62284 > y.y.y.y.https: P 306:729(423) ack 134 win 64107 09:59:49.378855 IP y.y.y.y.https > x.x.x.x: . ack 306 win 4685 09:59:49.378858 IP y.y.y.y.https > rx.x.x.x.62284: . ack 729 win 5108 09:59:49.379373 IP y.y.y.y.https > x.x.x.x.62284: . ack 729 win 5108 09:59:49.380508 IP y.y.y.y.https > x.x.x.x.62284: R 134:134(0) ack 729 win 5108