GRUB is giving an error while loading Windows 10

I’m getting an error while loading Windows 10 from GRUB menu. Ubuntu loads perfectly fine. And I can load Windows from boot menu tho, but that isn’t always a feasible option. I want my grub menu to work for both OS. I did a fresh installation of both OS on my lenovo G50-45 laptop.

Points to consider:
• Installed Windows 10 on 120 SSD.
• Installed Ubuntu 19.04 on 500GB HDD.
• Both drives are GPT partitioned and boots in UEFI.
• I disabled secureboot in BIOS, and fastboot, hibernation in Windows 10.
• I tried updating grub using “sudo update-grub”, where it detects the windows boot manager in the drive (/dev/sdb2) and I think it updates too, but it isn’t helping.

Here is how my disks are partitioned:

sda1 | 350MB | /boot/efi
sda2 | 30GB | /
sda3 | 8GB | [SWAP]
sda4 | 50GB | /home

sdb1 | 529MB | Microsoft Windows Recovery Environment
sdb2 | 100MB | EFI system
sdb3 | 16MB | Microsoft Reserved
sdb4 | 111GB | System files.

This is how my grub menu looks like

Advanced Options for Ubuntu
Windows Boot Manager (on /dev/sdb2)
System Setup

After selecting “Windows Boot Manager (on /dev/sdb2)”, instead of loading Windows 10, this is the error I get

error: no such device : 3C3C B62B.
error: disk ‘hd1,gp2’ not found.
Press any key to continue…

After pressing any key, it brings me back to the grub menu

While on grub menu,and after pressing ‘e’ for editing windows boot entry, this is what I get

setparams 'Windows Boot Manager (on /dev/sdb2)'           insmod part_gpt         insmod fat         set root = 'hd1,gpt2'         if [x$  feature_platform_search_hint=xy]; then             search --no-floppy --fs-uuid --set-root --hint-bios=hd1,gpt2 --hint-efi=hd1,gpt2 --hint-baremetal=ahcil,gpt2 3C3C-B62B         else             search --no-floppy --fs-uuid --set-root 3C3C-B62B         fi         chainloader /efi/Microsoft/Boot/bootmgfw.efi 

One thing I have observed is that, after changing boot priority to Windows drive, and again back to Ubuntu drive, the grub menu loads Windows successfully, but only once. The story repeats here after.

Can someone please help me solve this problem?