[Cataclysm Classic] Coloring error for unitframe mouseover tooltip

[Road-block]

Describe the bug

Got the Lua error in a dungeon (Coren Direbrew for seasonal event)
From the callstack (posted below) it appears to be on a player frame mouseover tooltip.

3x Blizzard_SharedXML/Color.lua:67: bad argument #2 to 'format' (string expected, got nil)
[string "=[C]"]: in function `format'
[string "@Blizzard_SharedXML/Color.lua"]:67: in function <Blizzard_SharedXML/Color.lua:66>
[string "=(tail call)"]: ?
[string "@TipTac/modules/ttStyle.lua"]:364: in function `GeneratePlayerLines'
[string "@TipTac/modules/ttStyle.lua"]:504: in function `ModifyUnitTooltip'
[string "@TipTac/modules/ttStyle.lua"]:792: in function `?'
[string "@TipTac/libs/LibFroznFunctions-1.0-35/LibFroznFunctions-1.0.lua"]:1418: in function `FireGroupEvent'
[string "@TipTac/ttCore.lua"]:3846: in function `SetUnitAppearanceToTip'
[string "@TipTac/ttCore.lua"]:3946: in function `?'
[string "@TipTac/libs/LibFroznFunctions-1.0-35/LibFroznFunctions-1.0.lua"]:1418: in function `FireGroupEvent'
[string "@TipTac/ttCore.lua"]:2152: in function `SetCurrentDisplayParams'
[string "@TipTac/ttCore.lua"]:2031: in function <TipTac/ttCore.lua:2030>
[string "=[C]"]: ?
[string "@Ace3/AceHook-3.0-9/AceHook-3.0.lua"]:95: in function <Ace3/AceHook-3.0/AceHook-3.0.lua:87>
[string "=[C]"]: ?
[string "=[C]"]: ?
[string "=[C]"]: in function `SetUnit'
[string "@PitBull4/UnitFrame.lua"]:256: in function <PitBull4/UnitFrame.lua:251>

Locals:
(*temporary) = "|c%s%s|r"
(*temporary) = "ffffffff"
(*temporary) = nil
(*temporary) = "string expected, got nil"

Steps to Reproduce

No clear reproduction steps outside of RDF.
Tried mouse-overing my player/target and raid frames, wasn't able to reproduce the error.

Expected behavior

No response

Additional context

I am using the Pitbull4 addon for all unit frames (player/target/focus/party/raid)

Version of TipTac Reborn

24.10.01

Flavor/Version of WoW

Cata Classic
WoW: 4.4.0

[frozn]

It seems that there was a player without a valid class name. To prevent this error I will alternatively show "unknown" for the class name if it's missing, but I'm curious which unit causes this error? 🤔

[frozn]

Fixed with 194b063. Will be included in the next release.

[Road-block]

I haven't seen this since the fix 👍🏻