I can provide preliminary confirmation of a bust on my Qnap TS-653 Pro running:
Firmware v4.3.4
HD Station v3.2.3
MC22 MediaCenter22_22.0.111-5_x86_64.qpkg
My Windows HTPC is no longer seeing the MC server on the Qnap NAS. I've done a reinstall of the qpkg but no change.
When I get off Daddy day care, Dad duty, I'll try logging into the Qnap via HD Station directly and see what it says. I'll report back with what I find, when I can - unless I get gazzumped and anyone out there feel free to jump in.
I suspect that with the change of Firmware / HD Station that occurred over the Christmas / New Year period, MC got the short shrift. You can probably point the finger at Intel's Meltdown (even if it's not justified) to be partly responsible.
The MC qpkg has been on borrowed time after Qnap did the dirty on JRiver, so I'm not holding out high hopes that Bob is going to burn a lot of effort to get this one sorted in quick smart time (unfortunately). On the upside, it's pretty easy to run MC in pull mode (my Qnap NAS shows up as a Samba file source, which is how I typically drag in video to my HTPC), so no biggie. You can also always run a VM on the Qnap if you've got the RAM and the rest, then set up a Linux (or Windows if you really want) instance and get a NAS based server operating that way. From a speed/bandwidth perspective, this only really makes sense to me if it's for audio. Video could work (not something I've tested) but I have my doubts.
EDIT: The bust was addressed by restarting the instance of MC. In my case, I went back to basics and reinstalled the qpkg. Logged into HD Station and started MC with no problem. The Qnap instance of MC shows up as a server in my local MC network.