This is another problem/bug caused by loading a saved skirmish game, this never happened to me before but still was kind of weird.
I dont know how to replicate but heres a video showcasing it, i was playing against intermediate AI on the season 5 pup, i however believe its also a bug on the live version of the game.
Mangonels were also bugged but it didnt show in the video
no reload time for mangonels and spingards after saving and loading a match - YouTube