Brave crashes when trying to leave Sync chain

[MDouglas345]

Description

User reported that leaving the Sync Chain on his Windows device causes Brave to crash. The original post -> https://community.brave.com/t/brave-crashes-when-trying-to-leave-sync-chain/263139

They were reporting that their passwords were being removed, made this post -> https://community.brave.com/t/passwords-lost-after-updating-to-version-1-25-68/253946

And then they tried to leave their Sync Chain to create a new one but now their browser is crashing; they have provided a video which is attached which you can view here -> https://drive.google.com/file/d/1UooChD96ZQt5QqmCN9zjcB1jamjrxLSD/view

Steps to Reproduce

1. Go to brave://settings/braveSync/setup
2. Remove all devices in Sync chain
3. Leave Sync chain (Sync chain is not leaved)
4. Refresh the page

Actual result:

Leaving Sync Chain crashes the browser

Expected result:

Sync Chain should not crash the browser

Reproduces how often:

Reproduces often.

Desktop Brave version:

Brave 1.26.67 Chromium: 91.0.4472.114 (Official Build) (64-bit)
Revision 4bb19460e8d88c3446b360b0df8fd991fee49c0b-refs/branch-heads/4472@{#1496}
Windows 10 Home

Android Device details:

• Install type (ARM, x86):
• Device type (Phone, Tablet, Phablet): Phone
• Android version: 5.1.1

Version/Channel Information:

Specific to Official

• Can you reproduce this issue with the current release? No
• Can you reproduce this issue with the beta channel? No
• Can you reproduce this issue with the nightly channel? No

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? No
• Does the issue resolve itself when disabling Brave Rewards? No
• Is the issue reproducible on the latest version of Chrome? No

Miscellaneous Information:

After crash, sometimes option to restore pages also does not come

I tried to replicate on Official and Nightly on Macos and was unable to; @Brave-Matt was also unable to reproduce on his Windows device.