Dear @Alvaro.Ponce.
Can you clarify what changes in the results when you drop the time step? Are you just changing the ElastoDyn time step, or have you tried changing the time step in the OpenFAST primary (.fst) input file?
A similar error regarding a singularity was recently discussed in the following forum topic: Wind Veer Parameter - #4 by Andre.White (see the posts between Aug 30, 2022 and Sep 1, 2022). Perhaps your model is suffering the same problem that can be fixed by disabling YawDOF or setting nonzero PtfmYIner?
Best regards,