NaN water height in ESM file is not handled gracefully

The problem happens with a simple mod that replaces the inhabitants of Addamasartus with undead spawn points.

To replicate use the attached .esp file, test.esp . Start the game in Seyda Neen and enter the Addamasartus cave.

The log will be spawned of error messages like and the FPS will fall dramatically.

[08:28:14.728 W] CullVisitor::apply(Geode&) detected NaN,
[08:28:14.728 W]     depth=nan, center=(-0.976732 0.13492 24.6744),
[08:28:14.728 W]     matrix={
[08:28:14.728 W]        -nan -nan -nan -nan 
[08:28:14.728 W]        -nan -nan -nan -nan 
[08:28:14.728 W]        -nan -nan -nan -nan 
[08:28:14.728 W]        -nan -nan -nan -nan 
[08:28:14.728 W] }

To have an idea here is a human-readable copy of the .esp file:

Record: TES3 "()" Flags:0x0000 ()
  HEDR:   Version:1.3  Is_Master:False  Author:""
  Description:""
  N_Records:1
 *MAST: Master:Morrowind.esm
  DATA: Length:79837557
 *MAST: Master:Tribunal.esm
  DATA: Length:4565686
 *MAST: Master:Bloodmoon.esm
  DATA: Length:9631798

Record: CELL "addamasartus" Flags:0x0000 ()
  NAME: Name:Addamasartus
  DATA: (Interior) Fog_Density:1.00  Flags:0x0003 (Has_Water)
  WHGT: Water_Height:NaN
  AMBI: Ambient:RGB=(20,20,20)  Sunlight:RGB=(19,21,21)  Fog:RGB=(22,44,44) Fog_Density:1.00
 *FRMR: ObjIdx:282952  MastIdx:1
  NAME: Name:in_tomb_all_lev-2
  DATA: X:-1308.073  Y:3695.677  Z:-553.602  X_Angle:0.0000  Y_Angle:0.0000  Z_Angle:2.1562
[... skipping similar FRMR records ...]
 *FRMR: ObjIdx:365600  MastIdx:1
  NAME: Name:Com_Chest_11_pos
  TNAM: Trap_Spell:curse strength
  DATA: X:-94.810  Y:5045.658  Z:-704.982  X_Angle:0.0500  Y_Angle:0.3000  Z_Angle:2.6500

• Is the problem OpenMW specific or does it also happen in vanilla Morrowind?

I cannot test in vanilla Morrowind because it does not work in my system.

• What is your operating system?

Archlinux Linux beerus 5.11.16-arch1-1 #1 SMP PREEMPT Wed, 21 Apr 2021 17:22:13 +0000 x86_64 GNU/Linux

• What version of OpenMW are you using? If you used a bleeding edge build, state the exact revision used.

0.47 3696187737

• What version of Morrowind are you using (i.e. retail CD or Steam)? What addons (Tribunal, Bloodmoon) do you have installed? What language is your Morrowind install?

I used the data from gog .exe file, extracted with innoextract. The language is English.