Error: Can't have a partition outside the disk!

[jishvi]

I'm trying to shrink a 200 GB boot disk (43GB of this disk is used) to a 50 GB disk on GCP. So I attached a 50 GB additional disk and ran weresync -C -L grub2 -g 1 /dev/sda /dev/sdb. But I'm getting this error upon running the weresync command.

weresync -C -L grub2 -g 1 /dev/sda /dev/sdb

Traceback (most recent call last):
  File "/usr/local/bin/weresync", line 11, in <module>
    load_entry_point('WereSync==1.1.5', 'console_scripts', 'weresync')()
  File "/usr/local/lib64/python3.6/site-packages/weresync/interface/cli.py", line 255, in main
    lvm_target, args.bootloader)
  File "/usr/local/lib/python3.6/site-packages/pydbus/proxy_method.py", line 75, in __call__
    0, timeout_to_glib(timeout), None).unpack()
GLib.Error: g-io-error-quark: GDBus.Error:unknown.DeviceError: ('/dev/sdb', 'Non-zero exit code', "Error: Can't have a partition outside the disk!\nModel: Google PersistentDisk (scsi)\nDisk /dev/sdb: 53.7GB\nSector size (logical/physical): 512B/4096B\nPartition Table: unknown\nDisk Flags: \n") (36)

The partition size created by weresync is greater than the disk size.

 sudo fdisk -l -u /dev/sdb

Disk /dev/sdb: 53.7 GB, 53687091200 bytes, 104857600 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk label type: dos
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048   105737510    52867731+  83  Linux

I followed the instruction in this article.

Can anyone help?