Why does use with air or water reduce the maximum temperature of certain high temperature / pressure hoses?

This example is a Parker Hannifin model 426/436 "SAE 100 R1 AT / SAE 100 R16 High Temperature Hose".

Here are the temperature specifications:

(Full data sheet)

Although there is an asterisk after the water/air notes, I can’t actually find any corresponding explanation in the data sheet for that.

I am actually looking into hoses for a compressed air application, so I’d like to understand the reason for this reduction in performance.