NAS not accessible from my network sporadically...with some other strange symptoms

https://preview.redd.it/v15aeymakxee1.png?width=1080&format=png&auto=webp&s=a8072acf2b1a33f9e6a00717a8d209e1fac636eb

Here is a chart showing my TS-873a availability on my network today....45% uptime, so that's been rough. This has been tested by pinging the NAS using uptime-kuma, every 20 seconds.

So I've been trying to get to the bottom of this issue with Qnap Support but no luck yet.

Initial symptoms:

- I was losing access to my NAS locally on my network

- All the other services running on the NAS (about 30), which had their own static IPs and were attached to a virtual switch, stayed accessible when the NAS became inaccessible.

- Those other services could access the NAS itself fine (ie. via its IP). Uptime-kuma saw no downtime for the same ping monitor as the image above, if it was running as a container on the NAS.

- Those services also could still access the outside world, so they could connect to the internet.

- As a result, I could access the NAS using a cloudflare tunnel, using a cloudflared container but couldn't access it via it's local IP address.

Things we've tried:

- No issues if I don't use a virtual switch...but then I can't do lots of other things

- disabling/turning off all 3rd-party apps, containers and VMs. Usually I have 1 VM and 30-ish containers connected to the virtual switch.

- tried swapping from NIC1 to NIC2 and the symptoms followed, as soon as I re-attached the virtual switch.

- Usually I have about 30 containers, with their own statically assigned IPs connected to a virtual switch.

I've now got static addresses assigned to both NICs, once directly and another via a virtual switch, then attached to my network via a physical switch. The NIC with the virtual switch attached and the virtual switch IP becomes inaccessible in a similar pattern to the above image but the directly assiged IP/NIC continues to work fine. This is making it a little easier to troubleshoot but it's not ideal.

Anyone ever come across this and have any other ideas I can try?