By raising her children indulgently, Stella ended up inviting disaster upon herself later on.
Literal
Children [object-を] spoil-[and-て] raised [thing-ことで], Stella [topic-は] later [self-自ら] disaster [object-を] invite [thing-こと][to-に] became-[unfortunately-てしまった].
A cautionary narrative. 甘やかす ('to indulge, to spoil') is the causative-like transitive verb related to 甘い ('sweet, lenient'). 災いを招く is a set phrase 'to invite disaster' — 招く ('to invite') used metaphorically. 自ら ('of one's own accord, oneself') emphasizes self-causation. ~ことになる ('end up X-ing, it comes to pass that X') marks an outcome that was not directly chosen. ~てしまう adds regret.