Sweat spots on different t-shirts

Yesterday I did some experiment: Place one Hanes 5250, one Gildan Ultracotton and one FruitoftheLoom t-shirt on the table, drop one drop of water on each. Each were 100% cotton. What I found was on the Hanes the water droplet spread immediately sideways, the size of the spot grew and the color of the spot was only a little bit darker than the dry areas. In case of the other 2, the water did NOT spread and created a small but much darker colored spot compared to the dry areas.
This matches with my experience while playing volleyball wearing these tees, the FOTL and the Gildan UC I looked like someone who just came out of a shower (or splashed with a bucket of water), while wearing the Hanes there was only mild signs of sweating and discoloring.

In Google searches I only found references to 100%cotton vs poly blends in the context of moisture wicking, they mention 100% cotton as one monolithic group of products.

Whats going on with sweat wicking at different brands of 100% cotton?