As spongeforge has updated to Mixin 0.8 recently, legacy transformers have been broken.
This will need to be updated to 0.8 https://github.com/TerminatorNL/LagGoggles/blob/master/src/main/java/cf/terminator/laggoggles/mixinhelper/MixinConfigPlugin.java#L177

Some problem. @TerminatorNL pls update mixin.

I'd quite like to start updating the serverpack I offer for my modpack, but I don't want to prevent people from using LagGoggles!

Heres a more in detailed error about it

https://gist.github.com/Alexandrea/153bbf9f22dbc5bfb78e8592749684e9

Heres a more in detailed error about it

https://gist.github.com/Alexandrea/153bbf9f22dbc5bfb78e8592749684e9

Yeah, because it needs to update mixins to 0.8 :)

There is a forked version that runs properly on 7.1.9 sponge

What's the name of the fork?

https://github.com/LXGaming/LagGoggles
You will have to build it yourself, he made updates

https://github.com/LXGaming/LagGoggles
You will have to build it yourself, he made updates

https://github.com/LXGaming/LagGoggles/releases/tag/1.12.2-4.9