Presidential ballot differed in two provinces

Description

I happened to be involved in the process of voting as an observer. On polling day I was deployed in one polling station in Harare. However because I registered in Goromonzi South, I got the surprise of my life. The presidential ballot used in Harare my polling station had a bluish colour inside. However when I went to Gorormonzi south the ballot paper was white and smaller. How is this possible if the ballots were supposed to be sequential and were printed by the same firm