Yes, as much as it's very annoying all the things in the game only remember which slot of summon you picked, not the summon itself.

So if you do replace your summon on slot 1 let's say from Monkey King to Tonton (for a nine tails) in this moment on Ranked, Arena, and Survival your slot one is Tonton and will break the combos for all these modes until you replace the summon in this slot again.

Sounds like thats broken to me.

Incorrect.

The fix to this would be to set the summon for ranked in each of your set slots

Summon 1: (PVP)
Summon 2: (Interchangeable)
Summon 3: (Ranked)

As long as you never change it, it'll always work for ranked.

Tobei, so you are saying the the slots are custom to your rules not the way we want to customize it. So 3 slots but you also have 3 sets of teams as well. So even if we were to set our summons up like you said, we need to make our 3 team slots in Ninja the same because if you switch a team slot that has a different set of summons your ranked battle summon still changes so in fact it is still wrong.

I was providing an example.
You may adjust it whichever way you prefer.

So, always set your ranked summon in one slot for each tab. (In case you change it)

Ranked doesn't take your in-game talents nor your ninja selections. Just that summon slot. Nothing else.
Your talent selection for Ranked is restricted only to that setting. The summon isn't. Which is why it's best advised to have one summon for ranked at all tabs.

Couldn't they just set it up so that ranked is completely separate with everything, I mean it makes more sense this way.

Could of, but unfortunately, that's how the system is and it's best to optimize it to the best of our abilities : )

The summon sets differ between teams (but only the 3 teams)
Only ONE of the slot per team need to stay the same. For me, that's the 3rd slot on all 3.
All my team uses 1st slot, if I were to actually change team, it would make sense to change the summon anyway, while I use 2nd for masuri and arena. That is when they are different from each other of course.
survival is so easy that it's not even a thing worth considering, I just use one of my main team that happen to share with my ranked, thou you could always switch to whichever team that always have the particular summon your survival uses.

The only real problem with this is the fact that there are often times I don't use as many gold summon as I could, because 1st/2nd slot is using a non-gold summon while I'm actually using the 2nd/1st slot for battle, which means missing some stat for no good reason. I could switch the non-active summon of course, but that risks messing up my other stuff. On this front, fortunately my ranked is using a gold, or I would always be running around with lower stat that I should.

So while not ideal, the impact is truly minimal.
Still, I would love separate summon set for masuri, survival, ranked and arena. If you can have different talents, you should have different summons.

Also, I really could use more teams....
I have one "main" team that I use for PvP, which happens to work for most PvE including survival, wanted, group instance, chase mission and most sealed ninja.

I have a tank-in-front(hinata, since I'm wind main, it's a girl team) team for 43200 TI and the water main sealed, since those two have a front row sweep. This also happens to work for exp trial (can complete extreme), however this team requires position change between the different activities (just no ninja change)

Then I have a 3rd team that is being used for fox, coin trial and group summon. The problem is, those 3 activity does not use the EXACT same set of ninja, rather they use 3 of 5 ninjas plus the main, and the summon and talent used for coin trial is different from the other two, there have been quite a few times where I went into fox with the wrong team and/or talent. (group summon is no big deal, since it's an easy kill anyway, coin trial no big deal since I can surrender and re-do. But going into fox wrong is BAD)

And then there is bloody Strong Approach, every week I have to swap one of my team around to do that annoyance.

Overall, I would really like at least 1 more (so I can keep fox consistent, I'm okish with sharing summon+coin trial), preferably 3 more (so I can split coin/fox/summon AND have one for SA) team slots.

And considering how multi-purpose some of my team are if you read what I do with them, I'm sure some people might need even more teams than me....

soooo... can we have like... 10? It's a nice, round, even number.

There will be more accessible slots in the future.

As for the knowledge of the summon slot being changed, that's up in the air.
I'll make sure to refresh the team about such suggestions and hopefully more forward with that idea.