Signatures stored in “Markup” are missing after iOS 17 and PadOS 17

Hey guys, new to community. Please let me know if my question is inappropriate or steps I missed.

Here’s the issue I identified.

I bought a new iPhone Pro 15 with iOS 17 built it.

Background

Back in previous versions of iOS or PadOS, there’s a feature to add signatures to Photo and PDF file.

Signature created is automatically stored and updated to devices under same Apple ID.

Therefore, the signatures I created on my iPad are available on my iPhone and MacBook.

Steps taken and Issues identified

After I restore iPhone 15 Pro with the back up of my iPhone 14 Pro, iOS 16.5, I found signatures stored in my Apple ID account was mostly missing with only the latest signature still available.

I tried to contact Apple Support and was asked to creat new signatures to test if the syncing among devices was functioning.

It turns out all signatures created either on iPhone 15 Pro, iOS 17, or iPhone 14 Pro, iOS 16.5, were able to synced among devices. But old signatures, created under iOS 16 or earlier version, is only available on devices on iOS but only the latest one available on iOS 17 device.

I updated with my iPad to PadOS 17.0.2 today and ALL SIGNATURES created on PadOS 16 or earlier version were all gone.

Primary working theory

Therefore, I came to the conclusion that iOS 17 and PadOS 17 might be the reason that my signatures previously are missing.

Request

Has anyone experience same issues? Or has already come up with the solution?

I was advised to re-create the signatures by imitating my old signatures but I don’t consider imitating as a fix to this problem.