Load your concrete bombs on any quantity and pylon, just load up at least one corresponding explosive variant on another pylon (I usually load up CFTs and external pylons with concrete and the center one with the explosive version). Then setup the A/G LOAD page in ARMT as supposed to, with the explosive version for every pylon (as the jet would start when hot and loaded from mission editor).
I found that inert bombs work this way, watch my third track for reference.
Matching as follows:
BDU-50 LD: Mk82
BDU-50 HD: Mk82 Snake Eye
BDU-50 LGB: GBU-12
Mk84 TP: Mk84 GP
I haven't tested BDU-33s, but I would try them with a Mk82.
Hope it helps for now, waiting for an official fix (by then I won't need concrete bombs anymore 🤣).
Pantera93's post in BDUs Rearm problems was marked as the answer