I took a break after landing on Gleba.
I tested for 10mins or so just stacking blueprints on each other and so far, it all aligned perfectly.
I don't know when I'll be spending extended time in factorio again, maybe later this year

Attached another clip of it happening. This time with a shift-click.
EDIT: The clip (9.6MB is failing to upload)
https://steamusercontent-a.akamaihd.net ... 0DCD4383D/

New proof there seems to be a blueprint issue with tracks, in this clip I ctrl+shift+clicked an "add-on" blueprint over the base blueprint and it marked corner tracks for deletion, even though it perfectly alligned and it was just replacing tracks with tracks, so nothing should have happened: https ...

Still a bug in that regard. As this was the start of my 2nd base, I purposfully did not want snapping. No 90% of everything was misplaces, as in the pic, some of the roboports replaced fine when ctrl+shift+clicking, at the bottom you can see it misplaced

I did use the advanced search before, but missed the one you linked.
Could be similar, but I am not sure as I only notice it in Remote View, and as I said, does not happen all the time, but in the video attached it happened twice.
Added the save and log.

Hi,

This is an intermitted issue I've been having where I could have swore I clicked correctly, but then when I come back, a duplicate off-center copy was build. I am note sure if this is blueprint specific, when building this blueprint I tried to be as symmetrical as absolutely possible to avoid ...

Same here, I don't think it's latency, me and a friend have 12-30ms ping most of the time peer-to-peer. It only started with 12.9 and happens even is you start a new muliplayer map. "Enable multiplayer latency hiding" does not seem to have an affect. Flashes about 1-3 times a second. V-Sync on or ...