Bosch Gen 3 CX and Chainring question

[Nick_V]

My sons Haibike ALLMNTN 7 ( 2017) with a Performance CX Motor has always suffered from chain suck, It has a 16T chainring and wondered if anyone else has upped say to a 20T. I am assuming the motors are configured with the stock size and does changing cause any issues ? Also anyone else been getting chain suck on the small chain ring and has going up a size helped ?