- Open a blueprint (or create a new one) that has some rails (and/or railroad stations) and also has some other entities with even size along at least one dimension.
- Filter out (or remove one by one) all rails (and stations) out of the blueprint.
- Click 'Export to string', then 'Copy', and 'Ok'. Close the blueprint (by pressing 'e' or elsewise).
- Open blueprint library. Click 'Import string'. Paste from buffer. Click 'Import'.
- Place a ghost with the resulting blueprint.
In the ghost from the resulting blueprint, all entities with even size along at least one dimension are shifted relative to their positions in the original blueprint (and also relative to their shown positions on the resulting blueprint). The shift is equal to -1 tile along dimension(s) along which the entities have even size (regardless of blueprint rotation). Some illustrations below.
Expected result:
The resulting blueprint working exactly like the original one, only without rails (as if they weren't there in the first place).
On the images, left to right: 1. arrangement from which original blueprint is taken (belts are placed as reference frame); 2. blueprint resulting from filtering out the rails, and exporting-importing the string; 3. ghost obtained by placing the resulting blueprint.
Images with some other entities
Note: For splitters the behaviour is a bit different: after step 4, on resulting blueprint (when in the hand, but not on preview from inventory) the belt segments are shown shifted from under the splitting mechanism by -0.5 tiles in both directions. Not sure if this is a separate bug or not.
Exchange string of the resulting (corrupted) blueprint with 4 splitters:
Exchange string of the blueprint taken from initial arrangement without the rails:
It seems quite probable that this bug is related to the fact that blueprints with rails are aligned to 2x2 grid, unlike all other blueprints (as mentioned here). However, I'm very interested to learn how exactly was it causing such behaviour, so I really hope that you would provide some brief explanation.