Timing chain jumps when turning engine by hand

[Chriscameron13]

Was seeing if anybody has dealt with this before and can lead me in the right direction, so a few weeks ago I put a new tensioner and timing chain and everything was running great then all of a sudden I go to start and it gave me P0016 and had super low power. So I dug back into it and it jumped timing somehow. I primed the tensioner before putting it in and the car is full of good clean oil. So I reset the timing and put the tensioner in there and when I go to turn the engine by hand about 1 revolution it gets slack in the chain and jumps. Please help! I’m stumped on this one. It’s an easy enough job it just doesn’t make sense why it’s jumping and running really great for almost a month.