Minion gem +1 level corruption bug

If you corrupt minion gem for +1 gem level, and this +1 level decreases spirit reservation, the reservation change will not be applied.

In my case: I use Skeletal arsonist gem. I have my main gem with level 6 - 37 spirit reservation per 1 minion.
I tried to gamble with vaal orbs on another Skeletal arsonist gem level 6. I got corrution for +1 level.
In description of corrupted gem it stated: "Reservation: 35 spirit".
But in reality it reserves the same 37 spirit as if it was level 6.

tl;dr: It seems like +1 gem level corruption doesn't apply to minion gem. (Doesn't lower amount of spirit reserved although in description stated otherwise).

Have same bug with other skills. I try to corrupt ilvl 16 gem with +1 and then use 17 to compare. ilvl 17 give more damage, this mean corrupted +1 dont work on any skill gem.

Also happened with my spark gem, in tooltips it's show higher lv but same dps.

Same thing with Lightning Arrow +1 Corruption.
Does not increase dmg/mana cost compared to regular lvl 16 gem.

i can confirm that arc and spark show same dps on lvl 20 and 21 corrupt, arc just upgrade the maximum chains.
and archmage buff have the same problem, lvl20 and 21 buff the other skills the same, and 21 should be the breakpoint.-
Can some dev explain if it is just a visual buf or what?

+1;

This isn't getting nearly enough attention - this is the only report of this bug I found in my search.

I've reproduced it with both comet and grim feast as well.

more bug information:

the tooltip when you hover the gem itself shows the higher +1 corruption adjusted base numbers and mana cost, but the advanced details, dps summary and mana cost when you hover over the skill on your hotbar remain at their pre-corrupted values.
 
Tested against another equal level uncorrupted skill gem, the damage, dps numbers, and mana costs for lvl19+1 and lvl19 comet are the same.

using grim feast to see actual in game amount of shield gained on remnant pickup varifies that the game is using the pre-corruption values.

+1 level corruption on skeletal brute gem bringing it from level 19 to 20. No change in any stats in the minion info.

Same here on frost mage 20 gem to 21 show level increase but not dmg increase in tool tip

Same here for titan stamped, basically it seems it is an issue with all skills. Please can this be looked into, spend a lot effort to corrupt it and turned out not improving, even tho the skill description says leveled up and increased damage, but dps value says otherwise.

Unless it is only a display issue and it actually work in fight??