I'm having a very peculiar problem with my vampire character since starting Morrowind again; after becoming a vampire, I do not get many of the skill or stat bonuses that come with it, nor immunities to disease or paralysis, or water breathing. I use Galsiah's (which has never given me any problem before) and it seems to be conflicting with the vampire mods somehow, despite the fact that I've loaded the appropriate compatibility patches. Also despite any skill increases my stats or level do not increase. I use the same load order for my vampire mods as I always have, the one recommended by Yacoby. Here is my full load order:

Masters for quiksave.ess:
001 Morrowind.esm
002 Tribunal.esm
003 Bloodmoon.esm
004 Morrowind Patch v1.6.4.esm
005 Better Heads.esm
006 Better Heads Tribunal addon.esm
007 Better Heads Bloodmoon addon.esm
008 THE Facepack Compilation.esm
009 THE Morrowind NPC Makeover.esm
010 TR_Data.esm
011 TR_Map1.esm
012 TR_Map2.esm
013 Better Bodies.esp
014 Galsiahs Character Development.esp
015 Resources Enhanced.esp
016 Balmora Expansion v1.4.esp (Version 1.2)
017 Slof's Vampire Faces.esp
018 abotWhereAreAllBirdsGoing.esp
019 vn_goldweight.esp
020 ImprovedTeleportation2.0.esp
021 Clean Better Daedric.esp
022 House of Earthly Delights, Harem Style.esp
023 FleeAIFixes.esp
024 Slof's Goth Shop 1.1.esp
025 k_weather.esp
026 Vvardenfell Druglord.esp
027 Book Jackets - Morrowind.esp
028 Book Jackets - Tribunal.esp
029 Book Jackets - Bloodmoon.esp
030 Slof's Goth Shop II.esp
031 Tribunal Relighted.esp
032 Bloodmoon Relighted.esp
033 Morrowind Relighted exVivec.esp
034 Lights_300_V4.esp
035 IceNioLivRobeReplacerALL.esp
036 IceNioLivRobeReplacerPLUS.esp
037 Dirty Deeds.esp
038 Decorator+ (Balanced).esp
039 To The Death.esp
040 Universal Companion Share.esp
041 Blasphemous Revenants.esp
042 Creatures.esp
043 Malq'ultrin Manor.esp
044 Piratelords Trade Enhancements.esp
045 New Argonian Bodies - Mature.esp
046 New Khajiit Bodies - Mature.esp
047 Aorawn's Race Mod.esp
048 Pursuit Enhanced.esp
049 Fliggerty's Almanac.esp
050 Westly Presents-Dremora Markynaz.esp
051 Gatanas Markynaz Dremora Companion - Male.esp
052 Animated Morrowind 1.0.esp
053 Census and Excise Office.esp
054 New Suran.esp
055 Scripted_Spells.esp
056 Vampire_Embrace.esp
057 Vampire Realism II.esp (Version 2.2)
058 Vampire Realism II - TB Add-On.esp
059 Vampire Realism II - BM Add-On.esp
060 Vampire Realism II - VE Patch.esp
061 Vampiric Hunger Base.esp
062 Vampiric Hunger Extended.esp
063 Vampiric Hunger MGE Addon for MGE 1.11+.esp
064 VampiricIllusion.esp (Version 1.4)
065 VampiricIllusion_MWSE_AddOn.esp (Version 1.4)
066 Diablerie.esp (Version 1.0)
067 Diablerie_MWSE_AddOn.esp (Version 1.0)
068 ScentOfBlood_VR.esp (Version 1.1)
069 ScentOfBlood_MWSE_AddOn.esp (Version 1.1)
070 ve_comp_control.esp (Version 1.2)
071 vampiric_regeneration.esp (Version 1.2)
072 GCD StartScript for Trib or Bloodmoon.esp
073 Merged_Leveled_Lists.esp
074 Merged_Objects.esp
075 GCD_SS_patch.esp
076 GCD_VH_patch2.esp
077 Better Clothes_v1.1.esp
078 PTE - BC Patch.esp

I also use the latest Morrowind Code Patch, the latest MGE and it's built-in MWSE.

EDIT: I'm also certain that this issue is solely between the vampire mods and Galsiah's; I loaded them by themselves and the problem persisted.

Have you tried anything from the Troubleshooting section of the GCD Readme such as the method for recalculating stats?

Yes, I have. The problem isn't just that my stats are off; as soon as I become a vampire, it's like the mod itself simply turns off. I don't level up, natural skill increases won't cause any corresponding stat increases, etc.

Does becoming a vampire increase your skills to beyond the skill slowdown point in GCD? This could make it seem as if nothing is happening.

Nope, start a new game, type in startscript vampire_aundae_pc, and the transformation happens, but at that point the entire levelling systems effectively breaks.