Its supposed to keep you moving foward and having a few cover your back while the rest fulfill the missions purpose. Don't let yourself get bogged down and keep moving toward the mission goal. BTW what lvl are you playing it on?

As I understand, the longer you stay during a mission, the more powerful the reinforcements get. They start being more frequent and with bigger pods, so you cannot linger around forever.

The level of Infiltration refers not to how many Advent are in the area, but rather how ready the are. If you infiltrate well, that means Advent will need to take longer to respond, giving your team more time to clear out safely. But sooner or later, Advent will respond in force, so get to Evac as soon as possible when you complete objective.

You can farm 1-2 groups of reinforcements for loot and XP, but you cannot last forever.

Advent will set traps for you in regions where vigilance has increased. The missions will appear easy due to the initial amount of enemies being low, but reinforcements will drop rapidly.

WAD

Also, reinforcements do not give exp and do not boost the amount of exp you receive for completing the mission

I'm with you. I'm done with LW2. Reinforcements every other turn. You can't kill enough of them before the next wave comes and then you're flanked (front and rear). Guaranteed, you'll have at least 3 of your team members that won't make it in a squad of 10. Really unbalanced. I'm on veteran. Ridiculous.

I have only encountered a couple of missions like that. To be honest some of the missions are supposed to be fights to achive the primary goal without killing every single enemy on the map. The evac can often be a contest to get out. Enemy death count is rarely the final goal

That's the big problem of this mod, this mechanic (like many others) is not appropriate at some places, there's too much inpredictable things which give us the illusion of a new attractive pleasant game but all we have at the end is tons of bugs, incomprehension and disappointement.
it's even worst when you know you have been enjoying it but you can't admit others things.

Its really amusing that we have this complaint across multiple discussions, when this mechanic occurs so rarely. It happens on the advent tower mission and trap missions. I've literally only seen it happen three times in normal missions across probably seven or eight lw2 campaigns

Your post is contradictory, how it can occuring so rarely if so much players went here to complain about it??
That's not because YOU have not this problem that everyone else too.
Think that each players have different settings, mods, config systems etc...
And 3 times is already too much imo
Having a free mod doesn't excuse everything.

3 times? I've run close to 300 missions since 1.1
3 times is nothing
its part of the game, not a bug, and it doesn't conflict with other mods, unless you hate yourself and you're running bigger pods or harder enemies

It's only happened to me this once, but thank you for the advice on there being more the longer you stick around this I was not aware. I was just taken aback by how many there were being the first time I'd encountered it. It's interesting adjusting to a new play style.

wait there are trap missions? so thats why i got a squad wipe by one drone...

What I can'f figure out is how you are supposed get out if you run into one of these damned things. I just had a mission where I initiated combat on the second turn. After killing two pods, incoming reinforcements were announced on my fourth turn. When more of them were announced on my fifth turn, I called the Skyranger. All told, I had four pods and four waves of reinforcements come at me (that's 32 aliens total). By the time my evac counter reported one turn left, I was outnumbered more than 3 to 1 and one of my own squad members was mind-controlled. Obviously, there wasn't any point in continuing. There was no way those soldiers were going to survive that last turn.

Now, the big question is: what the hell was I supposed to have done differently? I called the Skyranger as soon as I was informed of the second wave of reinforcements. Until that moment, there was no way for me to know that I was in trouble. It seems to me that the only way to prevent getting wiped out was not to go on the mission, but there was no way for anybody to know they should avoid it. This mission was apparently designed to wipe out any squad who was unlucky enough to actually initiate combat. This would have ended my campaign if I had been playing ironman, since I couldn't have continued after losing all those high ranked soldeirs, laser weapons, and mods. The only way for me to continue the game was to go back to a save that allowed me to abort that mission.

If you get reinforcements on the first turn, that's the big tell. At that point you start flash banging, pop smokes, hunker down, supress

Huh, I'd thought this was because I hadn't disabled Officer Reinforcements and LW2 lets yellow alert squads take non-shooting actions, which could include reinforcing.

Personally, I've mostly been stealthing as much of a mission as possible before engaging; if the first thing I do to reveal the squad is complete the mission objective, it'll usually go okay. Not really possible on the Liberation VIPs or eliminate enemy VIP mission, but for hacking workstations, stealing supplies, and so on? Hell, I've taken to sending lone stealth-trained Shinobi on Jailbreak missions; with the super short infiltration times and super small detection radii, sometimes ADVENT never even know they were there.