Reading same hgt file downloaded from two sources

I have two tiles for SRTM1 for the same bounding box region, but downloaded from two sources.

I read a value for a given latitude and longitude with python.
I get always a difference of one meter for the same latitude and longitude, I changed random numbers within the boundary, the same problem remains.
Then I opened both the hgt files with binary viewer, indeed there are not the same in binary.
My question is, which one should I trust and from where comes this error.

My python code:

import numpy as np

#https://e4ftl01.cr.usgs.gov/provisional/MEaSUREs/NASADEM/Africa/hgt_merge/
file_1 = 'n34e036.hgt'   #Source of file is from the link above

#https://cloud.sdsc.edu/v1/AUTH_opentopography/Raster/SRTM_GL1/SRTM_GL1_srtm/North/North_30_60/
file_2 = 'N34E036.hgt'   #Source of file is from the link above

SAMPLES = 3601 # Change this to 1201 for SRTM3

def read_elevation_from_file(hgt_file, lon, lat):
    with open(hgt_file, 'rb') as hgt_data:
        # Each data is 16bit signed integer(i2) - big endian(>)
        elevations = np.fromfile(hgt_data, np.dtype('>i2'), SAMPLES*SAMPLES).reshape((SAMPLES, SAMPLES))
        lat_row = int(round((lat - int(lat)) * (SAMPLES - 1), 0))
        lon_row = int(round((lon - int(lon)) * (SAMPLES - 1), 0))
    return elevations[SAMPLES - 1 - lat_row, lon_row].astype(int)

#test example
lat = 34.0 + (3599.0/3600.0)
lon = 36.0 + (4.0/3600.0)

elv_1 = read_elevation_from_file(file_1,lon,lat)
elv_2 = read_elevation_from_file(file_2,lon,lat)

print(elv_1)  # this yields 423
print(elv_2)  # this yields 422

Edit: I tried also for tile N52E009.hgt, there is also difference but here for two meters.

In binary viewer:
The right side is for file_2 and the left side for file_1