[MC-38596] I was at the "create new world" screen and as the terrain was generating it said "Shutting down internal server" twice. Then displayed the crash report.

I just downloaded the "Yogcraft" mod from FTB Launcher and installed a new texture pack. Everything went smoothly until the crash.

Linked issues

This ticket is invalid as it relates to a modified or 3rd party client, server, or launcher.

Any non-standard client/server/launcher build needs to be taken up with the appropriate team, not Mojang.
Any plugin issues need to be addressed to the plugin / resource pack creator.
This site is for addressing issues related to the base unmodded Minecraft.

I was conflicted to do so because the crash report said "report the .txt file to Mojang". But I suppose I will submit to....FTB, I guess.

Because you're running an ancient Minecraft version crash reports still contain that advice.