Potion effects from blocks and fluids aren't working

So, i made 2 fluids and 1 block which are supposed to give potion effects to the player. When the player stands on/in the block, the status effect is shown on the side, and the potion particles are there, but the effect does not happen. My theory here is that it keeps giving the effect on every tick, preventing the effect from taking place somehow. Is there some sort of "wait _ seconds" function in the procedures to negate this? if not, can the developer PLEASE add it in?

or if the problem is happening for a different reason, tell me.

the current procedure is:
Event trigger - triggered by external call
Add potion with level [1] and duration [8] to provided entity: POISON