Look at pic below :
https://i.imgur.com/UWMR4J1.jpg

How do i revert this mistake? I have no save file before this happen.
Is there any console command to delete those two slot ?

Edit :
I test using /c game.player.force.reset(), died and respawn.
It doesn't work, the two slot is persistent 😢

I can confirm this bug.
For example, you have 18 request slots researched. You start filling the request grid in the mod. When you fill all 18, the grid auto-expands and offers you 19th slot, etc. As soon as you press the apply button, your character grid is permanently increased over the researched limit.

/c game.player.character_logistic_slot_count_bonus = 0

But, yea, uh, the code in the mod is sort of blatant about this :

--kind of cheaty..
if slot_count < config_new.max_slot then
    player.character_logistic_slot_count_bonus = player.character_logistic_slot_count_bonus + (config_new.max_slot - slot_count)
    slot_count = character.request_slot_count
end

character_logistic_slot_count_bonus should be zero from what I can tell. That's in addition to your research. This mod cheats to make it higher to fill all the requests. That's ... fine. It would be too much effort to request a small set of items, and when they're full, request the next set of items -- all just to keep the game vanilla-friendly. And probably the whole line for slots research should be removed since it is literally doing nothing.

BUT what does need fixing:

When you clear the requests and don't need that many, it ought to reset the value back down. Right now I have... uh, 85 request slots, which is a tad too much. I don't know what exactly config_new.max_slot gets set but, yea, that's a lot.

character_logistic_slot_count_bonus should be zero from what I can tell. That's in addition to your research. This mod cheats to make it higher to fill all the requests. That's ... fine. It would be too much effort to request a small set of items, and when they're full, request the next set of items -- all just to keep the game vanilla-friendly.

Correct.
I could add a research to unlock the infinite request slots (and thought about it), but it seemed a bit pointless. If i don't research it, i can still have basically unlimited slots by creating multiple presets and load them one after another.
And code wise the current solution is way simpler, so i'll keep it for now (at least until the unlimited request slots/character gui overhaul announced in https://www.factorio.com/blog/post/fff-289 is implemented)

And probably the whole line for slots research should be removed since it is literally doing nothing.

Not sure what you mean by that?

When you clear the requests and don't need that many, it ought to reset the value back down. Right now I have... uh, 85 request slots, which is a tad too much. I don't know what exactly config_new.max_slot gets set but, yea, that's a lot.

Should be fixed in the latest update. It will shrink the number of request slots down just like the AutoTrash gui shrinks if you remove items. (Down to the last slot that has a request set, i.e. if you have 100 items set without a request and the last item in the gui has a request it would still show 101 slots in the vanilla gui)