does playing trifle counts as additional master phase for palatial estate?

Palatial estate allows vampire to get blood per each master phase, does trifle master card rule counts as additional master phase?

You're mistaking "master phase" and "master phase action".

Triffle says: "Trifle: Some master cards are identified as trifles. When a Methuselah successfully plays a trifle, they gain an additional master phase action. For an out-of-turn trifle, they gain a master phase action in their next master phase. A Methuselah can gain only one master phase action from trifles in a given master phase; any subsequent trifles act like regular master cards."(fron rulebook on Trifle)

You have only one master phase and you could have more than one master phase action

I do not think i have seen "additional master phase" effects in the game, as there is no additional "phase" effect, like additional "influence phase". Only option to play additional masters in form of "master phase actions".