First lets get the terminology correct.
'Chain suck' When the fails to disengage from a front chainring resulting in the chain pulled up and inot the chain stay. 'Chian suck' is strictly pertains to the underside of the front chainrings and can be caused by an excess of grime/crud/buildup on the teeth which leads to a poor release of the chain. Another cause is deformed chainring teeth, deformation doesnt allow the chain to release.