This is why Jeb is no longer permitted in the VAB

[Cat_Fish12321]

Hmm... Looks like something I had when using B9... The engines would show up as thrusting in the VAB and were playing the sound. Besides B9, I had like 15 million mods so that might be it. Not sure...

[Red Iron Crown]

It seems to be specific to my install (or at least, it wasn't reproducible on Pecan's install), so I'm not sure it's a valid bug.

[Padishar]

It seems to be specific to my install (or at least, it wasn't reproducible on Pecan's install), so I'm not sure it's a valid bug.

I saw another report of something very similar in the last few days (though I think it was with a solid booster). I'll try and find the post but in the meantime, I guess this must be some plugin that messes with engines so I suspect something like HotRockets (or RealFuels but I guess you're not using that). Do you use HotRockets?

[Red Iron Crown]

No, my PC is too underpowered for visual improvement mods (someday...). My mod list is as follows:

blizzy's Toolbar

Editor Extensions

HyperEdit

Kerbal Engineer Redux

Alternate Resource Panel

MechJeb

NavBallTextureExport

NavyFish's Docking Alignment Indicator

SelectRoot

cantab's SurfaceNodes (This is a less common one, adds radial attachment nodes to some parts that don't have them in stock)

TAC Fuel Balancer

Kerbal Alarm Clock

Tweakable Everything

I don't think any of these mess with the visual effects directly, but I could be wrong.

[Random Tank]

It looks like a plasma leak... Have you checked the reaction chamber casing? Splits or holes in it can vent hydrogen plasma instead of leading it to the exhaust.

[Red Iron Crown]

KSC now sealed off, KSP officials refusing to comment.

The drivers of the utility trucks drive through the nuclear rocket exhaust without hesitation. We think the kerbonauts are brave, but those guys are nuts.

[Robotengineer]

How is it doing that?

[S4qFBxkFFg]

This may be related - I had decouplers trying to fire in the VAB when I had the previous version of Tweakable Everything installed, upgrading to the latest version solved it though.

[Red Iron Crown]

This may be related - I had decouplers trying to fire in the VAB when I had the previous version of Tweakable Everything installed, upgrading to the latest version solved it though.

Hmm, turns out I'm not running the latest version. I'll update it tonight, test it and report back, thanks for the tip.

[cantab]

The drivers of the utility trucks drive through the nuclear rocket exhaust without hesitation. We think the kerbonauts are brave, but those guys are nuts.

We already knew that, considering the way they do powerslides in the trucks with huge tanks of rocket fuel hanging off the back.

[Red Iron Crown]

Updating Tweakable Everything (and Module Manager, which was packaged with it) didn't fix this. Thanks for the advice anyway, S4qFBxkFFg.