Unexplained Glitches

[WanderingPeanut]

Hey Hive, I've been working on a map of mine for quite a while now and as I'm nearly finished I discover a bucketload of serious glitches :/ I've now spent several hours trying to fix my problem and I'm pretty stumped. I'd like someone to fix my problem or just tell me what's going wrong, I'd like all the effort I put into the map not to go to waste.
Anyway my problems are as follows:

After some gameplay units that enter water will not be slowed as I intended, but will be instantly killed, (Ive tested a bit myself and this seems to start after lots of upgrades are purchased, but this just deepens the mystery for me) heres the trigger that controls slowing on water:

Trigger

• Events
  • Time - Every 0.4 seconds of game time
• Conditions
• Actions
  • Set zgrp = (Units in (Playable map area) matching ((Matching unit) is Undead Equal to True)
  • Unit Group - Pick every unit in zgrp and do (Actions)
    • set zloc = (Position of (Picked unit))
    • If (All conditions are True) Then do (Then Actions) else do (Else Actions)
      • If - Conditions
        • (Terrain pathing at zloc of type Floatability is off) Equal to False)
        • (Terrain pathing at zloc of type Walkability is off) Equal to True) (This should be deep water only)
      • Then - Actions
        • If Picked unit is in WaterGroup Equal to False then do (Unit Group - Add to Watergroup)
        • If Picked unit is in WaterGroup Equal to False then do (Unit - Add In Water (Book) to Picked Unit)
      • Else - Actions
        • If Picked unit is in WaterGroup Equal to True then do (Unit Group - Remove (Picked Unit) from Watergroup)
        • If Picked unit is in WaterGroup Equal to True then do (Unit - Remove In Water (Book) from Picked Unit)
        • If Picked unit is in WaterGroup Equal to True then do (Unit - Remove Buffs from picked unit)
    • Custom script: call RemoveLocation(udg_zloc)
  • Custom script: call DestroyGroup(udg_zgrp)

The second problem starts to happen at the same time as the first and that is when zombies kill a civilian (which is suppposed to reward 3 zombies) the 2 extra zombies are killed and only the one based off the dying unit remains, also when an ordinary unit is killed and it becomes a special zombie it will also be instantly killed. I've also noted that when the glitch kills a spawned zombie it has no death animation. The Trigger is here:

Trigger

• Events
  • Unit - A unit Dies
• Conditions
  • Unit Type of triggering unit equal to civilian
  • Killing unit is Undead equal to true
• Actions
  • Set civloc = position of dying unit
  • Set zplyr = owner of killing unit
  • Unit - Replace dying unit with a zombie using The new unit's max life and mana.
  • Unit - Set the custom value of last replaced unit to Random integer between 1 and 64
  • Animation - Play Last replaced units Birth animation
  • Floating Text - Floating Text Stuff
  • set zint = 0
  • set zint = 2+current research level of improve Leapers for zplyr
  • set zint = zint + Difficulty (this an integer either 1 or 0)
  • If Unit type of Killing unit Equal to Leaper then do Set zint = zint*2
  • If (All Conditions are True) then do (Then Actions) else do (Else actions)
    • If - Conditions
      • Custom value of Last replaced unit Greater than or equal to 2
      • Custom value of Last replaced unit Less than or equal to 2 + zint
    • Then - Actions
    • Unit Replace Last replaced unit with a Leaper using The new units max life and mana
• //Repeat for Other 4 Special Zombie Types

If you want to you can download and play the map on single player until the glitch occurs here. I would greatly appreciate any help and would give lots of credit.