On the file 'TSMGroupItemList.LUA' in TSM > GUI > TSMWidgets there is a single refrence to Battlepet tooltips, that breaks this function.
To Fix
Line #131, "row:SetScript("OnLeave", function() GameTooltip:Hide() BattlePetTooltip:Hide() end)"
Remove 'BattlePetTooltip:Hide()'
To "row:SetScript("OnLeave", function() GameTooltip:Hide() end)"
fixes this.