I'm having a similar issue to what TheSquirrelofHuscurl commented on in the mod's main page. Might not be entirely the same problem source, but the "Big And Small" mod causes the male bodies to graphically break, making the leg fur end up too far to one side while the skin layer is missing. I assume it's missing because it's a separate layer from the leg fur and this skin layer becomes replaced by the error box texture. This only affects the male body type and not the female body type.

I know very little about code, but I reckon there might be some line of code that the Big And Small mod is calling for that it finds in the female body type but not the male. As for what that code would be I have no idea. Furthermore, if TheSquirrelofHuscurl does not have the Big And Small mod then it's likely there are several other mods that have a similar issue where they are calling on code that the bun female body type has that the males do not.

(As a side note, the THIGAPPE mod doesn't work with the Bun's body types, causing all clothing to completely disappear no matter what they wear. This is likely due to a simple incompatibility on the THIGAPPE mod's end so I plan on letting them know, but if you'd be willing to also reach out to them in search of a fix that would be appreciated. Update: It appears that the Buns being naked due to THIGAPPE is a known issue. The solution is a complete clean install of THIGAPPE and all the mods it needs. Unfortunately this did not work for me, so I'm still seeking a solution.)

Here's an error message that popped up in relation to the "Big And Small" graphical glitch:

Failed to find any textures at Bun/Bodies/ while constructing Multi(initPath=Bun/Bodies/, color=RGBA(1.000, 0.937, 0.788, 1.000), colorTwo=RGBA(0.659, 0.000, 0.620, 1.000))
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Verse.Log:Error (string)
Verse.Graphic_Multi:Init (Verse.GraphicRequest)
Verse.GraphicDatabase:GetInner<Verse.Graphic_Multi> (Verse.GraphicRequest)
AlienRace.AlienRenderTreePatches:BodyGraphicForPrefix (Verse.PawnRenderNode_Body,Verse.Pawn,Verse.Graphic&) (at C:/Program Files (x86)/Steam/steamapps/common/RimWorld/Mods/AlienRaces/Source/AlienRace/AlienRace/AlienRenderTree.cs:182)
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.PawnRenderNode_Body.GraphicFor_Patch2 (Verse.PawnRenderNode_Body,Verse.Pawn)
Verse.PawnRenderNode/<GraphicsFor>d__69:MoveNext ()
Verse.PawnRenderNode:EnsureInitialized (Verse.PawnRenderFlags)
Verse.PawnRenderNode:EnsureInitialized (Verse.PawnRenderFlags)
(wrapper dynamic-method) MonoMod.Utils.DynamicMethodDefinition:Verse.PawnRenderTree.EnsureInitialized_Patch1 (Verse.PawnRenderTree,Verse.PawnRenderFlags)
Verse.PawnRenderer:EnsureGraphicsInitialized ()
CharacterEditor.Capturer:PrepareForRender (Verse.Pawn)
CharacterEditor.Capturer:GetRenderTexture (Verse.Pawn,bool)
CharacterEditor.Capturer:UpdatePawnGraphic (Verse.Pawn)
CharacterEditor.CEditor/ModData:UpdateGraphics ()
CharacterEditor.CEditor:set_Pawn (Verse.Pawn)
CharacterEditor.PawnxTool:PostProcess (Verse.Pawn,CharacterEditor.PresetPawn)
CharacterEditor.PawnxTool:SpawnPawn (Verse.Pawn,CharacterEditor.PresetPawn,Verse.IntVec3)
CharacterEditor.PlacingTool:PlaceInPosition (Verse.Pawn,CharacterEditor.PresetPawn,Verse.IntVec3)
CharacterEditor.PawnxTool:SpawnOrPassPawn (Verse.Pawn,RimWorld.Faction,CharacterEditor.PresetPawn,Verse.IntVec3,bool)
CharacterEditor.PawnxTool:AddOrCreateNewPawn (Verse.PawnKindDef,RimWorld.Faction,Verse.ThingDef,CharacterEditor.PresetPawn,Verse.IntVec3,bool,Verse.Gender)
CharacterEditor.CEditor/EditorUI/BlockPawnList:AAddStartPawn ()
CharacterEditor.SZWidgets:ButtonImage (single,single,single,single,string,System.Action,string,UnityEngine.Color)
CharacterEditor.CEditor/EditorUI/BlockPawnList:DrawTopBottons (int,int&,int)
CharacterEditor.CEditor/EditorUI/BlockPawnList:Draw (CharacterEditor.CEditor/EditorUI/coord)
CharacterEditor.CEditor/EditorUI:DoWindowContents (UnityEngine.Rect)
Verse.Window:InnerWindowOnGUI (int)
UnityEngine.GUI:CallWindowDelegate (UnityEngine.GUI/WindowFunction,int,int,UnityEngine.GUISkin,int,single,single,UnityEngine.GUIStyle)