Factorio Forums

To reproduce this issue, do the following (all of which should be done remotely, far enough from the base that it will take bots a few seconds to build everything):
1. Place 2 assembling machine 3s, vertically adjacent
2. Wait for them to be built, and request speed modules to be placed in them
Before the speed modules are actually placed, do all the following:
3. Copy both assembling machines, and place a copy that's partly overlapping, so there's now 3 assembling machines, 2 of which are built (the other a ghost) and all of which have unfulfilled module requests
4. Undo the last step

Expected result:
Step 3 should be undone, but both assembling machines should still have module requests

Actual result:
The bottom assembling machine no longer has module requests

(This probably happens with any combination of machine/module)

Edit: this might be related to viewtopic.php?t=132411