Xml filter plugin - creating nested field out of null object: Can't get text on a END_OBJECT

Elastic Stack Logstash
10

Ok, so looks like I can remove completely and it resolves the issue. I guess im still curious how/why it gets pulled in as a nested field instead of empty string.

Finally, my last question is how would i remove that field ONLY when it is empty? Since it isn't an empty string field and instead an empty nested field the following hasn't worked:
this one fails to fulfill condition:

if "" in [entry][ApplId]{
	mutate { 
		remove_field => [ "[entry][ApplId]" ] 
	}
}

this one actuates EVERY time:

if [entry][ApplId][]{
    mutate { 
        remove_field => [ "[entry][ApplId]" ] 
    }
}

so is there a way i can write a condition which will remove the field only when it is empty, and not all or nothing? When there is information presented in ApplId i would prefer to keep that field.