failed to run region growing implementation using python

Question

I'm trying to run an implementation of region growing for point clouds using python based on the documentation given by pcl. The shown error appears:

C:\Users\youss\AppData\Local\Temp\ipykernel_13008\2969360685.py:23: RuntimeWarning: invalid value encountered in arccos
  if all([nn_cur in order , np.arccos(np.abs(np.dot(normals[seed_cur[seedval]],normals[nn_cur])))<theta_th]):

The code:

import math
import numpy as np
from sklearn.neighbors import KDTree
unique_rows=np.loadtxt("All_floor.txt")
tree    = KDTree(unique_rows, leaf_size=2) 
dist,nn_glob = tree.query(unique_rows[:len(unique_rows)], k=30) 
def normalsestimation(pointcloud,nn_glob,VP=[0,0,0]):
    ViewPoint = np.array(VP)
    normals = np.empty((np.shape(pointcloud)))
    curv    = np.empty((len(pointcloud),1))
    for index in range(len(pointcloud)):
        nn_loc = pointcloud[nn_glob[index]]
        COV = np.cov(nn_loc,rowvar=False)
        eigval, eigvec = np.linalg.eig(COV)
        idx = np.argsort(eigval)
        nor = eigvec[:,idx][:,0]
        if nor.dot((ViewPoint-pointcloud[index,:])) > 0:
            normals[index] = nor
        else:
            normals[index] = - nor
        curv[index] = eigval[idx][0] / np.sum(eigval)
    return normals,curv
def regiongrowing1(pointcloud,nn_glob,theta_th = 'auto', cur_th = 'auto'):
    normals,curvature = normalsestimation(pointcloud,nn_glob=nn_glob)
    order             = curvature[:,0].argsort().tolist()
    region            = []
    if theta_th == 'auto':
        theta_th          = 15.0 / 180.0 * math.pi # in radians
    if cur_th == 'auto':
        cur_th            = np.percentile(curvature,98)
    while len(order) > 0:
        region_cur = []
        seed_cur   = []
        poi_min    = order[0] #poi_order[0]
        region_cur.append(poi_min)
        seedval = 0

        seed_cur.append(poi_min)
        order.remove(poi_min)
#        for i in range(len(seed_cur)):#change to while loop
        while seedval < len(seed_cur):
            nn_loc  = nn_glob[seed_cur[seedval]]
            for j in range(len(nn_loc)):
                nn_cur = nn_loc[j]
                if all([nn_cur in order , np.arccos(np.abs(np.dot(normals[seed_cur[seedval]],normals[nn_cur])))<theta_th]):
                    region_cur.append(nn_cur)
                    order.remove(nn_cur)
                    if curvature[nn_cur] < cur_th:
                        seed_cur.append(nn_cur)
            seedval+=1
        region.append(region_cur)
    return region
region1  = regiongrowing1(unique_rows,nn_glob)

I've searched and found that this error is because the value given to arccos should be in the range[-1,1] but don't know where is the cause nor how to fix it!