When a Complex Object property is ruled by filesystem or capability metadata, when the value to complete is already complete (full file name, full capability name), the completer miss behave.
In this case, the completer doesn't propose the "," or "}" character that allows to continue Object completion.

Another case of invalid completion for complex type:
For example:
/subsystem=logging/logger=xxx:add(filter={any=

{level=ALL}<TAB>
The Parser will parse internally that onto:
/subsystem=logging/logger=xxx:add(filter={any={level=ALL}

}
That makes the value-type completer to consider that the filter property is terminated and will propose content in a wrong context. By chance, tha tis not visible because it falls in a case where ',' is proposed. So the problem is hidden.

It is visible with the computed visibility and deployment:
/deployment=xxx:add(content=[{bytes=bytes

{0x45}<TAB> ==> must propose /deployment=xxx:add(content=[{bytes=bytes{0x45}

}