There can only be one 8e Régiment d'Infanterie de Ligne on the list, especially if both are in EU. As would be the usual standard, the one founded first has first rights to the name. Both were apparently founded on the same day, but Maxonovien's FSE thread was created an hour and a half earlier.
With that being the case, Maxonovien's regiment will be the only one added to the list. If some sort of deal is worked out between your regiments, I might put the second one on, but until then, Max's is the only one added.