Observable not updating when a method is called from a nested component

[PoojaC94]

Discussed in #6392

^{Originally posted by PoojaC94 September 22, 2022}
I have a FAST component which has multiple components in it
Component A
const template = html<item> ${when x=> x.isComponentOpen, <componentB></componentB> }
<componentC :onClick={(x)=>x.onClick}></componentC>

@observable isComponentOpen = false;
onClick() { this.isComponentOpen=true }

When componentC calls onClick, the isComponentOpen is set to true but componentB is not appearing. Why does this happen?

[KingOfTac]

Resolved in linked discussion