Hi there Hootenanny!
As I live in Asia I've been using an Australian brand as it's one of the only few available CG products around here. The brand is "Sukin Australian Natural Skincare" and I've been using the "Nourishing Conditioner." These are the ingredients:
Aqua, Aloe Barbadensis Leaf Juice, Cetyl Alcohol, Cetrimonium Chloride, Sesamum Indicum (Sesame) Seed Oil, Glycerin, Hydrolized Wheat Protein, Triticum Vulgare (Wheat) Germ Oil, Persea Gratissima (Avocado) Oil, Simmondsia Chinesis (Jojoba) Seed Oil, Rosa Canina Fruit Oil (Rosehip), Tocopherol, Urtica Dioica Extract (Nettle), Arctium Lappa Extract (Burdock), Equisetum Arvense Extract (Horsetail), Phenoxyethanol, Benzyl Alcohol, Citrus Tangerina (Tangerine) Peel Oil, Citrus Nobilis (Mandarin Orange) Peel Oil, Lavandula Angustifolia (Lavender) Oil, Vanilla Planifolia Extract, Citrus Paradisi Extract (Grapefruit Seed), Linalool, Limonene
To my knowledge these ingredients are CG-friendly. It would be very interesting to see what other products and ingredients other curlies with the same problem have been using. I also wonder if there's a particular ingredient that could be causing problems across the board. It might be hard to figure out though.