Incorrect effect duration in /effect give

When runing /effect give <player> <effect> <duration>, the <duration> is either an amount of seconds or infinite, however when the effect is either instant damage, instant health or saturation, instead of the effect lasting said amount of seconds, it only lasts 1/20th of that amount (possibly because the game is applying the effect for <duration> ticks instead of <duration> seconds).

Steps to reproduce:

1. Create a new world with commands enabled

2. Run /effect give @s <effect> 1000 where <effect> is one of the 3 mentioned above.

3. Open your inventory to check the effect's duration.

Expected behaviour:

 - The effect given in step 2 should last 1000 seconds (or about 16 mins 40 seconds)

Observed behaviour:

 - Instead, the effect is only lasting 50 seconds, yet if its any other effect, it lasts the intended 16 mins 40 seconds.