What have I done?

[Xragill]

I have no idea what I have done.... 

I upgraded Combustion beam to the max, and it gave me no indication that I was exceeding the limit on my ignis.

Edited February 3, 2017 by Xragill

[PoisonHD]

Huh, no idea how you did that with a primary

It's "simple" with a waframe or melee weapon though.

[PsiWarp]

Nevermind, that is strange o3o

Edited February 3, 2017 by PsiWarp

[Xragill]

No I don't have any keys

[Telluric]

It's just a bug that can happen when upgrading mods from your mod segment. Sometimes it gives you the option to remove it, sometimes it doesn't. My Sancti Castanas are -2 capacity because of this.

[Night4ce]

My Penta has a -4. It's a rare glitch but a nice one to happen when you already have a full build.

[Theiyre]

Are you trying to get this patched?  Because that's how you get this patched.

[Tomppak]

Well, I want to point out that if you go negative capacity, your weapon's (damage?) mods stop working. See how your dmg output dropped there?

So, don't try to exploit it, you'll just be shooting yourself in the leg.

[Arezael]

It used to be common to see this happen as for example: Cryo Rounds for the longest time cost 9, and when it was patched to 11, the game didn't remove it from being equipped.

I still have a few builds on weapons I rarely use that are -1 or greater and blink red at me if I go into the upgrade screen for that particular Primary. There are a few ways to achieve this, but none worth pursuing.

Your damage drop is also related to using Magazine Warp - it's something I'd advise you avoid. Use Wildfire if you absolutely have to have a Magazine increase on the Ignis.

Edited February 3, 2017 by Arezael
Clarification