Enemies levels issues (Defence missions)

[Smaksost]

In the alerts missions, I took a defence mission, they told me that my enemies will be between level 14 and 16 max (14-16), but when the mission started the lowest level I saw is 21, why they are lying to people?
Before I started the defence mission, I prepared my "Excalibur" warframe for fighting enemies between level 14 and 16, but they brought me enemies between 21 and 25.
I will give an idea of what I was understanding, for example:
If they wrote that I will take a defence mission with enemies that have levels between 14 and 16, then normally if I play the first waves until the first extraction available, I should play with enemies that do not exceed level 16, but if I chose to continue fighting the waves until the second extraction available, then in that case I should expect enemies with any level, this is what I was understanding in the beginning, but now, I don't understand anything anymore, what is the point of writing enemies levels different from what I'm going to fight?

[EDM774]

There's a thing called enemy scaling. The first wave of the defense or survival (or any endless game mode for that matter) will be the specified level (in your case 14-16) but with each wave passed they scale up. Ever wondered why some ppl like to test their limits saying stuff like I did a X hour survival to see what lvl enemies I can kill. Sanctuary onslaught is a sped up version of that actually where the scaling happens at a faster rate. Just FYI if you manage to do a 15k cryotic excavation (AKA 150 excavators) run on a dark sector vs infested, around the 140-150th excavator enemy level is 4K (lvl4173 but who's counting 😄)

[Smaksost]

I know that there is a level scaling, and even if there is a level scaling, in my case from the first wave until the first extraction available, the scaling should be from 14 to 16, that mean the first round should not exceed level 16, but the second round it can, for exemple:
First round: level increase from 14 to 16 until the first extraction available .
Second round: level increase from 16 to 20 until the second extraction available .
Third round: level increase from 24 to 26 until the third extraction available .
Fourth round: level increase from 30 to 34 until the fourth extraction available .
And so on ............
So the rounds should keep going like this until the player can't handle some level, but in my case, the first round my enemies level was from 21 to 23, in the first time, I told to myself, this is just a mistake, so I aborted the mission, and then I re-entered to the alerts missions menu and I started the same mission again to be sure, so in the beginning of the mission, just after the first alarm, all the "grineers" spawned with levels 21-22. so this is a permanent issue, and not a mistake, if no one believed me, next weekend I will take many defence missions from the alerts, and I will upload an uncut video on youtube, and then I will show you the issue(if the issue persists).