GS510TLP Port flapping

a) So the switch is new and I had no issues prior to the switch install.  Was using a GS108T

b) never tried the default factory firmware. It is still available on image2 and is 6.6.2.6.  On installation I updated the firmware and configured the settings.  I ran it for about a month and observed this port flapping and TCP connection failure issues across all devices - I've been too busy to fix. I will attempt to try the factory firmware after a few more days of testing.

c) Internet Sky Q => GS108T (now swapped for an old FS105 dumb switch 100MB) => GS510TLP => Computer, WiFi, TV etc

I've had everything disconnected apart from the FS105, Sky Q and the GS510TLP and WiFi and the problem is still there with this new switch - it was not there before I bought it.

Yesterday, I disabled the SNTP (made it local time) and lo and behold the mental time checks (every few seconds and sporadically in bursts) have stopped (obviously, because it's now off) but also the port flapping appears much reduced and possibly cured.  I won't declare it solved yet as 1 days isn't suffient in my eyes.  So I'll monitor.  If I confirm SNTP issue then I'll report back - I'll also try the 6.6.2.6 to see if the problem exists there.

Changes from DEFAULT config is that I disable STP, set SNTP to 0.uk.pool.ntp.org

Have tried: IGMP OFF (think it was on but also had the problem before I turned that off), ARP renew is now OFF but had the issue before this was changed .

I have just noticed that DNS is enabled but no DNS server entered.  I can't remember if I had this set before with SNTP.  I have factory reset a few times since.  Anyway, SNTP with no DNS server (but set to enabled) was the last known config that was causing this issue (with STP off also).