I have been repeatedly getting a "must align with rail grid" floating error message above blueprinted bins when placing blueprints. But it doesnt happen all the time, only with some blueprints, and even separate blueprints of the exact same area/components one may cause the error and the other not. My guess it that it is somehow related to how the blueprint is made, and or the fact (another bug?) that the bins do not show up in the blueprints. Another clue may be that (a) it only seems to happen with horizontally placed bins, and (b) when i get the error, the errant bins are placed vertically instead of horizontally.

Some of this can be seen in my quick demo video here https://youtu.be/YWs6Bq_5t3c. Several mods can be seen to be in use, however since it does not always error I don't think the mods are the issue. Also manual building and copy/paste do not seem to cause the error.

Update: I just noticed something that backs up a thought above ... it only seems to be the unloader bins that are affected, and to the point above, the loader bins show up in the respective blueprints while the unloaders do not.

Using "select new contents for blueprint" on a blueprint in the blueprint library is completely broken for mods. If you need to update a blueprint with new contents, move it to your inventory first and then update it there. Even this isn't completely reliable because of the same bug. It's best to pretend the "select new contents for blueprint" button doesn't exist.

https://forums.factorio.com/viewtopic.php?f=48&t=88100