Crowded joins-- but I did add that 2nd pair of arm+hand in another save!

[Mike B]

I cant seem to add this arm, but I know I added the same exact one in another save. I have grafting maxed and just have a right arm/hand connected. Note, I fixed this by casting regrowth.

[Jochen Terstiege]

Hm, I could graft the left arm, followed by the left hand without any issues.

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[Jochen Terstiege]

You have the tentacled mouth corruption which interrupts spell casting. Maybe this was the issue?