Hi May,
Indeed this fix was pushed to the 4.17 release, as other, more critical bugfixes/tests had to be pushed first. The release date on the 4.17 update is 1st of november – I can see that happening, some more of the features had already been finished.
While we are at it, something that I cannot wrap my head around is the “network of networks” term. Does native WordPress supports connected multisite networs of some sort? I was under the impression that each network has to be a separate installation.
I did a bit of research at the time, but I could not find anything. I was hoping to do some more research, once I get to this issue – but if you can help me, that would be great.
Is there a specific configuration I need to enable this feature? Are there any resources I can read on the WordPress website for the official documentation? That would help me tremendously to understand the issue – as implementing secondary index tables would be a major rework, and probably extremely difficult as well. I am hoping to do a different solution if possible.