FortiGate Next Generation Firewall utilizes purpose-built security processors and threat intelligence security services from FortiGuard labs to deliver top-rated protection and high performance, including encrypted traffic.
Article Id 224812
Description This article describes when 'Clone Reverse' is missing in policy.
Scope FortiOS.

'Clone reverse' is not always available by design. It is hidden when:


  1. Action = 'ipsec'.
  2. NAT is enabled.
  3. Interface 'any' is selected.
  4. VIP is selected for dstaddr/dstaddr6.
  5. Mac address is selected for srcaddr/dstaddr6.

This issue is fixed on FortiOS 7.2.4:
Resolved issues | FortiGate / FortiOS 7.2.4 | Fortinet Document Library
and it is possible to upgrade to that version to have this option back again.