I use my 10x farm boosts to plant all upgrades for the hour. I have yet to get more than 42 minutes completed before I get kicked out. I have written tickets and posted on forum and been told there is no problem, working as intended. However, I asked 4 or 5 times if any S8 employee actually tried doing that on android w a 2 gig tablet and Never got a yes or no!!!
If I boost with rushrooms, that lesser quantity seems to work but the game can't handle doing 7 plants every 1 to 2 minutes for an hour. You can see the game labor and take longer to bring up screens as the time goes on. It really looks as if the game is going to the nether regions of its memory and when it's got no more poof!
I really wish they would investigate releasing memory, reusing it, possibly allocating more to run the game. I don't know if any of those are possible but I don't think they really bother to even check what I've told them.