EtImmortale

Hmm, unless the Give Feedback and Report Bugs buttons are a target of modded expansion I wonder if they could be replaced into...or at least one of the two into a mods button... Maybe even another to see the dedicated server mods...but that's troublesome... Anyways nobody is going to report modded bugs to mojang right?

Odd, seems to be a lwgl issue, a context can't be created... Outdated opengl maybe?

Give more details like the forge version, target mc version so the devs have more context and have the install log ready if they need it, other than that you have a weird issue...

Found it. It's because they share the same tag:cobblestone Since both stair recipes are with the same tag and shape it conflicts. Still there as of forge 28.1.22