As shown in picture, the pawn actually chooses a shell farther away, ignoring shells nearby put in shelf. If there are no shells outside shelves, pawn will not operate the mortar at all. Should be a bug, as they could pick shells from shelves in earlier versions.
(I play vanilla RimWorld and the mortar was set to shoot explosive and EMP shells)
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(I play vanilla RimWorld and the mortar was set to shoot explosive and EMP shells)
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