So I'm a new player (on my second fortress, first was lost to birds) and I've experienced a very odd series of events that I'm not sure how to parse. How many of these are bugs, and how many are just weird results of mechanics, I'm unsure, so if a more experienced player could let me know I'd appreciate it.

So this all starts with a river. My fortress, despite being in a very tolerable climate, was chronically deprived of reliable water sources, leading to several of my best soldiers dying of thirst in the hospital due to lack of potable water. Vowing to prevent this tragedy ever happening again, I channeled a massive man-made river around my fortress from deep underground, providing additional safety as well.

However, in the process I endured several goblin raids. Due to the position of the riverbed between my fort and the goblin attack direction, conflicts would almost always happen near the riverbed while it was under construction. This led to most of the goblins dying within the dry bed of the project. So be it, I thought. The river shall be their tomb, so I left their bodies there.

Enter the Queen. Happy with my extremely chill and beloved Mayor Duchess, I intentionally avoided giving gifts to the Mountainhome to avoid potential royalty arriving uninvited to add additional headache. Yet despite this, at a certain point, the Queen decided to show up anyway. Arriving unceremoniously, her entourage consisted of...herself. Well, her and the outpost liason, but just them. No additional royalty, no combat ready manpower, just them.

I assume this was due to my fortress being at capacity when she decided to show up. However, while not in her entourage, she did bring a very ominous group with her. From ALL around the borders of the map (not just her arrival direction) unannounced nobles flooded in. I'd wager about 15 or so. They weren't visitors, but they weren't added to my fortress count either.

I assumed they would eventually wander off or get killed, but they didn't. Instead, they all stumbled into my mostly flooded riverbed. Now to be clear, there were numerous drawbridges and access points they could have used instead. Indeed, while they shambled forth, my woodcutters nervously crossed right by them over a nearby bridge as they plunged into the rapids.

I assumed this would hasten their deaths and rid me of a potential problem, but...it didn't...

They now reside underwater, standing there. They have been there for nearly 3 years. They are not hungry or thirsty. Instead, their only thoughts are horror and nervousness at the surrounding goblin corpses lining the riverbed. Assuming they were stuck, I halted the water flow and provided slopes and stairways for them to escape, but no results. They remained steadfast in their determination to remain with the dead.

So now they're a permanent fixture of my fortress I guess. A bunch of wandering nobles in eternal horror at the bottom of my river. Additionally, since they showed up, scattered limbs of goblins I had left in the river have begun...raining into my fortress below. No water leakage to speak of, just the corpse parts and forgotten armaments of the goblins falling into my guild forum and rotting in the thoroughfare. I assume this is just a result of the water physics pushing these objects through solid rock by accident, but I thought the coincidence was funny and flavorful.

So yeah, very confusing and moderately unsettling. But at least I didn't get more nobles in my fort.

Edit: Here are a couple images. I swear there were more of them last time I checked, but they either escaped when I wasn't looking or are stacked on each other or something. At least they're happy to improve their swimming I suppose.