So firstly I haven’t been awarded the amount of hero power-ups that are stated getting 1 or 0 when I should be awarded 3/4 and 4red heroes and 1 o8 hero(all level 140 and max skilled) couldnt defeat a level 40 boss 
You aren’t guaranteed any power-ups. It’s random in what each of the rewards gives you, you may come away with 3-4 one time but only 1 another time.
Which heroes were you using?
Your own boss always gives 1-2 powerups (usually 1), and other bosses usually give 0 but can also give 1-2. Breaker quests can occasionally give 1 and reaching 20 quest milestones gives you 5.
Nowhere can you get 3-4 in one hit 
For some reason I thought I’d gotten 3 from 1 bot before 
. Maybe that was after collecting rewards from multiple bots.
I thought so too
I’m sure I’ve received 3 before, guessing its about drop rates for them.
It said on the rewards list though, counted them - but then when I checked how many I’d recieved in my ‘inventory’ I got 0.
Heroes: gonzo/peep/elsa/kristoff &sven/ olaf - I can usually one shot up to level 100 with these,
It could have been through multiple bots since they are grouped together now, regardless I never received
3 power ups from your own bot is possible but rare, I’ve never seen anymore than that.
I am having this problem too. It may have only started for me at level 250 bots. Also possible the grouping of bots that wasn’t supposed to be in game yet is missing one of the categories after wins. On my last bot, it was my own and I killed it in one run. Rewards list showed 2 powerups and I received zero. I did not notice it abnormal until the last few runs, but had read this post. So I checked.
Nevermind. While taking screenshots I realised the problem. With the new system it is listing the total at the top and I was adding that with the other categories. So doubling the rewards I thought I should get. It is not a bug just momentarily confusing.