It could well be that the Carnival Event or Settlements or something else may have triggered an increase in lag/issues at recalc.
That happens also, but AGAIN, I'm not referring to lag issues @ recalc, and would appreciate it if these are not conflated. I feel it's important at this point to decouple what I suspect are problems which are always present and @ low server load from those @ high load and peak times as well as during events, both in the conversations in forums like this, and in bug reports, because we cannot have an honest dialogue as to the fate of GvG in the long term, nor short term feasible solutions to address acute problems, between the company's interests and players interests, when there is confusion as to what the problems and complaints are. athena9 posted a list here of issues which I have seen independent of time of day and when events are not running. YES, we all know that the events are not the culprit... another straw man to knock down. I'm not blaming the events.
So, let's try and ISOLATE the issue shall we? Autobattle was introduced, YES... Great milestone there, and I'll even go so far as to argue in Inno's favor that by increasing the speed at which battles can occur, and raising the throughput, you're also raising the bar on customer expectation. and naïve users might complain about lag even though compared with pre-autobattle, they're getting more fights in... ok great... but the problems I just posted about, the ones do appear to have some kind of relationship with the symptoms Athena listed for you. I understand that autobattle is creating a larger load, just as you put forth, so it stands to reason that behaviors manifest at a much lower threshold now, absolutely... but here's the rub: Autobattle was running perfectly fine for a good length of time with events starting and stopping, and yet these problems did not yet exist... they were introduced more recently! I don't know if you hit some critical threshold in load which manifested new behaviors, as I've not been involved with your engineers and in testing on your end, but I know what I see on my end, and it's a change above and beyond the time of autobattle's introduction over a span of multiple months and events. I did not come here to post until the more recent problems that have been described. Was there some other straw that broke a camel's back? Perhaps, but it looks like a bug to me. Members in our guilds think the other side is cheating with bots or scripts all the time, too. I caution against filing bug reports too quickly into the bin of traditional background noise on a tired issue. It's in the company's best interest to fix low hanging fruit rather than dwell on intractable issues. Like I said, this is more like autumn 2018 introduction. There's a few she didn't include in her list, like time desynchronization between client and server. For me, anyway, this was not happening before... yet autobattle and events were happening. I have seen it long ago, but you simply reload your browser on rare occasion it occurs, but this is now something chronic which can affect other aspects of the game. For example, you go to double-dip on a plunder and instead you default to pol/mot on the building instead of the first plunder because your local clock is still counting down to reset your 24h action, but the server clock is real time. I've seen gaps as wide as 3 full minutes you can drive a truck through, quite possibly related to GvG.
On the more long term problems, and on the economic reality of extending GvG lifespan with 0 or negligible capital investment, and fewer complaints, grab the low hanging fruit if there are bugfixes to be made, but yes at some point you may need to make unpopular decisions, but maybe we have an honest stakeholders meeting and make it a popular one, and not by PR trickery, but by delivering a GvG 2 or something like that for mobile also. If you are sincere that GvG is a small, or insignificant part of the product, though I may caution as to indirect relationships, why define guild rank, something so central to goal oriented behavior and therefore reason to spend diamonds, build your city, etc, have the entire metric of a "score" all boil down to one insignificant part of the game you've made an economic decision to no longer support? You appear to be in contradiction there and can't have it both ways without undue strife. That's a whole new thread in and of itself.
One last thing... Please let's all try not to confuse changing reset time with decoupling tile protection @ server reset on tiles any more. One is a radical game mechanic change, the other is window dressing in ignorance of the core issue, which is the NEED for players to be on in GvG regardless of when that time is, be it 1, 2, 3, 4, etc... there's a need to be on then, hence more traffic. (granted you can avoid (internet* rush hour globally by doing so and cause and tweak how many users will re-arrange their personal schedules). Neither is a "real" fix from my perspective, but if you wanna talk minimal capital investment and keeping the patient alive on life support, let's at least be honest there. I will say that you might have more luck getting away with the tile decoupling and it might make more sense to do that now given the situation, but I'm not in favor of it. Just my opinion, but simply changing your metrics on global guild rank might be a smarter decision for the company, but its another death pang for GvG mk 1. Some of us still remember the old days before server clock and tile protections