When using /effect, the time of the effect given to a player doesn't match the time it the chat says

When I am using the /effect command: /effect @p minecraft:saturation 100 10, it gives me saturation 10 for 100 ticks, not 100 seconds. The chat says it gives me saturation for 100 seconds but in my inventory it only says 5 seconds. I'm not sure whether the bug is that the chat is wrong, or if the command is not giving the effect for the correct time.