1) Are you talking about the popup that the reliever is getting tired or the actual green stamina bar? Because I found the Reliever getting tired popup just pops up somewhen after 20 pitches or so for the relievers later in the game. Doesnt matter whether they are actually low on stamina or have 80 stamina rating
2) Cant say I have a problem with that, i'm running my 7-men bullpen so that I always give my relievers a day off after pitching, just like its handled in real life too. And with that only rarely my reliever has not regained full stamina by the time im putting him in the game again. Like that only happens if he had to pitch a high number of pitches or two innings.
But Setup man #1 has full stamina and pitches 1 inning on Monday.
Then setup man #2 has full stamina and pitches 1 inning on tuesday
By the time its wednesday, my Set up Man #1 has normally regained all of his stamina and is good to go again and thats how it goes with all of my bullpen.