To simplify the display, the remaining periods are rounded: we speak in days if there are more than 24 hours left for the campaign to succeed, and in hours if there are less than 24 hours left.
Whether there are 24h01 or 47h59 for a campaign to succeed, the Animal Webaction counter will therefore display 2 days remaining. This is why the time displayed for a campaign goes directly from 2 days to 23h.