Verified commits in PR are showing up as unverified in target branch post merge

Question

Can someone help me with this ??

I am following the below steps to push my changes to the main branch:

1. Create a temp branch out of latest main

2. Edit files and stage my changes

3. Commit to the branch in local using below command:

   git commit -m <message> -S

4. I do get a prompt to enter passphrase, I enter it and I get the signed commit. Verified the signed commit both in github UI and command line too:

   git log -1 --show-signature

5. Post this, I create a PR using this branch onto the main. Even the commit in PR shows the commit as verified but post the merge of PR, the commit in main branch shows up as unverified.

What could be the reason behind ??

I did check that my GPG keys are configured appropriately in github and further the git configurations are also set fine in my local which is why i presume that i can see the verified tag for the commits in branch and also in PR.

Not sure why it is disappearing in target branch after merge.