I just got the same error trying to create a multipatch from a utilities polygons feature class using an elevation TIN file I just created from a raster. I tried creating the multipatch inside and outside of a file geodatabase but got the same error. The multipatch is actually created despite the error, but is missing some features (~200 of 12,000). I don't see any rhyme or reason to why some weren't converted while others were.
multipatch feature #arcgispro 2.2