diff --git a/CREDITS.md b/CREDITS.md
index 181d17374f..de808d5d7a 100644
--- a/CREDITS.md
+++ b/CREDITS.md
@@ -749,6 +749,7 @@ This page lists all the individual contributions to the project by their author.
   - Allow replacing vanilla repairing with togglable auto repairing
   - Fix an issue that the time for units in the area guard mission to reacquire targets after eliminating the target is significantly longer than that in other missions
   - Framework for dynamic sight
+  - Fix infantry with Engineer=yes ignores cell occupier in AreaGuard, Parol and Guard mission
 - **solar-III (凤九歌)**
   - Target scanning delay customization (documentation)
   - Skip target scanning function calling for unarmed technos (documentation)
diff --git a/docs/Fixed-or-Improved-Logics.md b/docs/Fixed-or-Improved-Logics.md
index a411072e9b..fb5e1a3bbd 100644
--- a/docs/Fixed-or-Improved-Logics.md
+++ b/docs/Fixed-or-Improved-Logics.md
@@ -324,6 +324,7 @@ This page describes all ingame logics that are fixed or improved in Phobos witho
 - Enabled playing ingame movie in non-campaign modes (i.e. trigger action `100 Play Sidebar Movie...` and `117 Play Sidebar Movie and pause...`).
 - `ElectricAssault` weapons can now auto acquire allies' overpowerable defenses.
 - Fixed the issue that the time for units in the area guard mission to reacquire targets after eliminating the target is significantly longer than that in other missions.
+- Fixed infantry with Engineer=yes ignores cell occupier in AreaGuard, Parol and Guard mission.
 
 ## Fixes / interactions with other extensions
 
diff --git a/docs/Whats-New.md b/docs/Whats-New.md
index 7948163e7a..e48473e25f 100644
--- a/docs/Whats-New.md
+++ b/docs/Whats-New.md
@@ -652,6 +652,7 @@ Vanilla fixes:
 - Enabled playing ingame movie in non-campaign modes (i.e. trigger action `100 Play Sidebar Movie...` and `117 Play Sidebar Movie and pause...`) (by TaranDahl)
 - `ElectricAssault` weapons can now auto acquire allies' overpowerable defenses (by Ollerus)
 - Fixed the issue that the time for units in the area guard mission to reacquire targets after eliminating the target is significantly longer than that in other missions (by TaranDahl)
+- Fixed infantry with Engineer=yes ignores cell occupier in AreaGuard, Parol and Guard mission.
 
 Phobos fixes:
 - Fixed the bug that `AllowAirstrike=no` cannot completely prevent air strikes from being launched against it (by NetsuNegi)
diff --git a/src/Misc/Hooks.BugFixes.cpp b/src/Misc/Hooks.BugFixes.cpp
index a3f758c224..3d89681193 100644
--- a/src/Misc/Hooks.BugFixes.cpp
+++ b/src/Misc/Hooks.BugFixes.cpp
@@ -3513,3 +3513,6 @@ DEFINE_HOOK(0x707A2E, TechnoClass_PointerExpired_TargetExpired, 0x5)
 	}
 	return 0;
 }
+
+// Fix infantry with Engineer=yes ignores cell occupier in AreaGuard, Parol and Guard mission.
+DEFINE_JUMP(LJMP, 0x51C335, 0x51C41C);