Hi Aniona, thanks for the post!
Market bots, and bots in general, are a pretty pervasive problem. There are the FC bots we've been discussing as well as "lone-ranger" bots like the one you describe. On the Crystal Server, I've found at least one of these "lone ranger" bots that sell items on multiple servers. I bet your server also has the FC bots like the ones we've been discussing as well.
Altogether, after spending a lot of time on a few servers, I've found that each server has a minimum of 4-6 market bots, which I would characterize as follows:
1. 1-2 FC bots. Each server has at least one FC with one crafter and about 8-9 dummy accounts for RMT trading. These FCs are typically in the top 20 ranking for the server. I suspect that these FCs are all run by the same RMT company (like 4000GOLD) or RMT person, and from what I've seen, they've contaminated all servers and datacenters in the US and Europe.
2. 1-2 Lone-ranger bots. These are bots often don't participate in an FC. They spread their goods to all servers in a datacenter and drop prices, like the FC bots, within tens of minutes on a 24/7 basis. I found at least one of these on each of the Aether and Crystal datacenters. I suspect this is a different RMT company using a different way to exploit the market.
3. 3-4 Player bots. Many players have realized that the only way to compete with market bots is to run their own bots. These player bot accounts will play the game during normal hours then they'll go into market bot mode to undercut competitors within tens of minutes. It's not unusual to see these player bots in price wars with the other bots by taking turns undercutting 20-40 times per day. The number of these is a bit difficult to identify, but if you spend a day in a market, you'll notice them.
This is not to mention the DOL bots that everyone has seen and identified. In the level 80 zones, it's pretty common and typical to see 3-6 or more bots stacked on top of each-other, doing the exact same script in mining ephemeral nodes.
Quality job SE.