hi,

I add points in solver sop ,but there are some duplication point number. Is it a bug?

Thanks!

No, that's not a bug. The number returned by addpoint() is more of a “temporary” id, and not the final id. The addpoint VOP mentions this:
https://www.sidefx.com/docs/houdini14.0/nodes/vop/addpoint [sidefx.com]
You can use the returned id with setpointattrib, but it shouldn't be stored beyond that vex execution.

Maybe one way to workaround this is to only mark which points are new, then use a separate wrangle to get and set the new point id? See the example hip file.