Do you have any scalp issues? Have you recently switched away from sulphate shampoos? Harsh chemicals can increase shedding in susceptible individuals - permanent dye, harsh shampoos and alkaline soaps for example.

Beneficial ingredients for colour treated hair include coconut oil, hydrolysed protein, ceramides and panthenol. Emollients (fatty alcohols and cationic surfactants) are also important ingredients for helping it maintain hydration, softening and reducing friction - they are your basic conditioning agents. For scalp care there are many beneficial ingredients, but particularly products at pH 4.5 to 5.5, aloe vera inner leaf gel.

I wouldn't use that mask if you are conditioner only washing, neither mineral oil nor cetyl esters are water soluble so it isn't fully Curly Girl friendly; shea butter in the curl enhancing smoothie can also build up although it's probably not the issue if you are not using that regularly.

Your Hydra Charge is not a true leave in conditioner in that it does not contain any fatty alcohols or cationic surfactants. Like your deep conditioner it is humectant heavy, without balance in your routine with occlusives/ sealants (penetrating and natural oils), emollients and proteins porous or damaged hair could very easily dry out.
"Water, Propylene Glycol, Vinylamine/Vinylformamide Copolymer, Peg-40 Hydrogenated Castor Oil, Phenoxyethanol, Polyquaternium-4, Parfum/Fragrance, Disodium Cocoamphodiacetate, Hydrox Yethylcellulose, Lactic Acid, Hexyl Cinnamal, Methylisothiazolinone, Benzyl Alcohol, Linalool, Amyl Cinnamal. F.I.L. D55681/2"
Garnier Fructis Hydra Recharge Moisture Whip Leave-In Conditioner for Dry Hair - CVS pharmacy

Overall I think you are not conditioning properly or in a balanced way, humectants without sufficient emollients and occlusives, possibly not enough protein. There are some great articles on ingredients on the Natural Haven blog and here on NC by 'curl chemist' Tonya McKay.
2a-2c, medium texture, porous/ colour treated. Three years CG. Past bra strap length heading for waist.

CO-wash: Inecto coconut/ Elvive Volume Collagen
Treatments: Komaza Care Matani, coconut/ sweet almond/ fractionated coconut oils, Hairveda Sitrinillah
Leave in: Fructis Sleek & Shine (old), Gliss Ultimate Volume, various Elvive
Styler: Umberto Giannini jelly, Au Naturale styling gelee
Flour sack towel, pixie diffuse or air dry.
Experimenting with: benign neglect