Pathfinding issue, enemies glitch through walls

How about adding a always condition to check if an enemy is close to a wall, like one pixel, and if so they are deleted or whatever.

Does this happen all over the game or just at specific areas or walls? If so, you could place hidden objects at just the problem areas so that if they overlap that object something happens. This may not be a perfect solution but perhaps reduce the occurrences.

You stated the problem occurs: "usually when they continuously collide with a wall"

Is that one time? 5 times? 1 second? 5 seconds? Set an event or counter to prevent the "continuously collide" action of the zombie.

To solve the problem you need to find an event of the zombies behavior you can trigger on or change the design of your game.

It appears the problem occurs when the zombies are near the wall and overlap each other. Try adding a command to prevent the the zombies from overlapping. Post an update when you do.

I've been looking at your game. I believe I see the problem. Do you want any standard zombie to gain access through the wall? Do you want any Kamikaze zombie to gain access through the wall? Do you want any Big zombie to gain access through the wall?

Are you sure about the Kamikaze zombies? It looks like they can or should be able to fly over the wall?

I found a solution to your game glitch problem. It took some time and a lot of testing but I finally got a workable solution. See you private message.

I was glad to hear the example I sent you solved the specific problem you asked about.

To address your other question: I don't know what your full game specs are so I cannot give you solutions for scenarios I am unaware of. You are correct in that the pathfinding extension needs some work when a lot of actives are involved. The glitch is real. I am not aware of another pathfinding extension however.

Recommendations:
1. Report the Pathfinding Bug to Clickteam. Show them the example I sent you.
2. You have to be specific in showing the scenarios you need help with. It looks like you have a good start but you need to show what the "real" game will look like and what the "real" problems are. Sometimes you have to program with what you have and refine the design to get what you want. Try different approaches like I did during testing.
3. I am not aware of another pathfinding engine.

Well the code will work with a small change. The safe zones need to be part of a group so that if any zombie touches or overlaps a safe zone it is destroyed. That code is simple. The tricky part is where to recreate the zombies due to the problems with the pathfinding algorithm. This needs to be at the corners of the enclosed areas and should be done in a random way so the user does not know it is happening.