Super Robot Wars/J/Bugs

Shield Defence

If the シールド防御 (Shield Defence) ability activates on a counterattack against a unit that has moved before attacking, it will fail to actually reduce damage taken.

Missing Parts

Parts equipped to certain units will vanish when the units are removed or swap pilots due to the story. This happens to the Strike Gundam, Great Mazinger, and Venus A.

Missing Parts Pt 2

Similarly, some units that upgrade to another form will keep ghost parts equipped. This happens with Layzner/Layzner Mk II, Yuu Brain/Nelly Brain, and Mazinger Z/Mazinkaiser among others. The new unit will retain the effects of the parts even though the part itself will return to your inventory.

Gai's Return

On the first play of the game only, Daigouji Gai will receive double the intended automatic bonus when he returns (as if 8 routes had not included him instead of 4).

X Aestivalis

The X Aestivalis can be used to cause odd effects at certain story events. If Ryoko is deployed in it at the end of Mission 33, she will be forced into her personal Aestivalis in Mission 34 but will still receive credit for kills made with X. If Akatsuki is deployed in X when he's supposed to leave the party, his personal Aestivalis will be removed but he will remain as a pilot.

Graimkaiser

If the Graimkaiser is not acquired on the first playthrough of the game, it will not receive its intended stats when later acquired, instead starting with no upgrades.

Wrong Subpilot Image

Normally, if the male main pilot is chosen, deploying in almost all missions with a particular subpilot will flag her as the main pilot's love interest, resulting in a special conversation at the end of the game. However, it is possible, having deployed with one subpilot through all other missions, to swap pilots at the last possible moment and have the wrong portrait display during the conversation despite the dialogue being that for the intended ending.