Which is a logistics problem.
Up to date, every X-Wing expansion has been self-sustainable, which means that every box cames with all necessary cards, dials, templates and tokens to be playable by itself.
However, with extra munitions, though the respective boxes (TIE Punisher / K-Wing) include ordnance tokens, they seem not to include duplicate mine tokens.
With seismic, proton (and likely ion) bombs there's no problem since they self-detonate and remove themselves immediately from the board... But with Proximity Mines, Cluster Bombs and Conner Nets there may be a problem because they are (likely to be) persistent... If we duplicate the load with Extra Munitions, we can easily find ourselves out of tokens to put on board and use them both at the same time.
For example, let's say one turn I drop Cluster Mines using an ordnance token. Assuming they behave like persistent proximity mines... And even assuming that my opponent collides and detonates one or two of them in the same round... If the next turn I want to drop them again, there's literally not enough tokens available for me to reproduce them, unless the respective mine tokens all disappear from the board.
So, either you can't launch 'persistent' mines till you recover all your mine tokens... Or an extra copy of them should be put in the box, which by the way, should also include an additional 'Proximity mine' token, to enable duplicity for the already launched expansions.
Of course all this operates under the assumption that those mines behave as 'persistent' tokens. But from the lore and the looks of them, it seems likely.