Lately—I stopped editing for about six month and recently jumped back in—I’ve noticed that things are acting strangely with the default editor (iD). And now I have video proof!!!
Sometimes, I will move a node or one of those triangle-thingies (in ArcGIS, we’d just use an “Add Vertex” tool; in iD, you grab the little triangle thingy…does it have an official name?) to a new location and…??…the damn vertex (I’m sorry…Node) simply moves back. Its really galling when working on the crap TIGER linework…that stuff is really ugly! But if that’s what OSM really wants, then why bother using crowdsourcing?
Here’s the video. (or https://youtu.be/MTbPX1e4Th0) Please let me know a work around or if I should just let the frustration get the better of me and I give up making contributions. I’m that peeved right now.
Use left Alt when dragging, this seems to do the trick.
This may be a bug. See, the line is a member of two multipolygon relations, each of which describes outline of a wetland, in one relation with role outer in the other with role inner. This doesn’t make sense and something is probably broken here with the data. It may be that iD doesn’t understand this and one of its protections against breaking relations kicks in which you can override with left Alt.
BTW, if you are comfortable with ArcGIS, you may like JOSM too, so try it out. It doesn’t attempt to outsmart the user 
JOSM’s validator spits out some vague multipolgon errors, and I see these are your fresh edits, so it won’t be checked on KeepRight which updates weekly.
Anyway, data probably needs to be fixed in this place, so do ask on the US sub-forum, I don’t have time to investigate it.
As an aside, don’t be so frustrated and assume somebody makes such bugs on purpose… 
OPTION (er, Alt-key)?!??! Wow! That worked!!! Thank you! Where is that documented, anyhow? Sometimes the simplest of things seem like they’re really, really buried deep somewhere…usually in a bad place.
I downloaded JOSM, and I’ll play around with it. I really wish (sigh!) that it was more intuitive. QGIS is intuitive, for instance. I’m still attempting to figure out how to zoom into an area in JOSM to edit something. Once I figure that out, then I’ll need to figure out how to make those edits. OSM is a lot of unnecessary work; sometimes I wonder why I do any of it other than I really enjoy mapping.
I’m sorry, but I don’t assume that such things are bugs. Instead, I assume that they’re “features.” A lot of software engineering involves saving us, the users, from ourselves…that’s why there’s an iPhone App Store. Ok, maybe there’s other reasons, too, but I’ve been given that excuse a few dozen too many times. And Keep Right? Wow! that’s nice! I sure wish I knew about that ages ago! Yeah…more frustrations with documentation…
Thank you for your help. Please mark this Help Ticket as resolved!
-Ken