Hone 22
I think that statistically most engine failures happen within 100 hours of rebuild/reman. If the aircraft went in without the problem you mention and came out not quite right it's a cause for concern.
You mentioned you had light off but no increase in N1 at all.
During the start attempt did the gages fall to zero? For a 206 this is a last chance indicator of bad battery.
Did the health checks for that engine (and topping check) after rebuild show the engine as positive and staying or was it rapidly decreasing in performance?
Lots of variables to look at here but don't let safety become one of those variables. Best place to find something wrong is on the ground.
Let us know what's found please,
Thanks