I can confirm this is not normal. Could you tell me the name of the mission exactly and on which device you are playing? (PC or Android) and if possible, which version (Android version / Windows 10 or 11)
Are you playing the free version? (If so then it was a mistake for it to be there to begin with) if you're on the subbed version, it's because Dregan's shop is now unlocked only after you've completed Dregan's story (which includes summoning Sol)
Ok The mission can now continue. But there is another problem why did Dregan in Renown shop disappear?