Normally when category settings are unchanged, checking the "Constant seeding" setting will override the "Upload ratio limit" and cause the torrent to continue seeding even when the upload ratio is exceeded. However when you set an upload ratio limit for the category, it overrides the constant seeding setting on individual torrents and stops them when they reach the limit.

I think it would be better if the behavior was more consistent, preferably the constant seeding setting would always take precedence over the ratio limit, regardless of if the ratio comes from the global setting, the category, or the individual torrent.