Having strange issue with IPSEC tunnel

I have created a IPasec tunnel between 2 FGT Ipsec tunnel is properly configured  have phase 1 192.168.2.0/24 phase 2 has 10.10.5.0/24 & 10.10.6.0/24 have same policy for both 10.10.5.0/24 & 10.10.6.0/24 range. now issue is from few system 192.168.2.x range am not getting connectivity to 10.10.5.0/24 range but 10.10.6.0/24 are getting connected. I have monitor the log the traffic is reaching to FGT local LAN port for that particular system but no traffic on 2nd fortigateon log , for 10.10.6.0/24 i can see log on both fortigate that traffic is moving. this very strange issue  Update: now with testing i found that even number IP are able to access 10.10.5.0/24 network (i.e .32 &.172) but ip address end with odd number are not ( I.e. .65 & .169) but from that able to access 10.10.6.0/24 network thanks in adavance Vishal