Adding a signature causes a 'Link Annotation Modified' or 'Stamp Annotation Modified'

Hello,

I have two scenarios:
1. Link Annotation Modified

If I have a document with Table of Contents and I add add 2 Digital signature on page after ToC, I get a 'Annotation Modified' - Link annot on page 2 on the Signature panel for the first signature. Page 2 is ToC

2. Stamp Annotation Modified

I have another document with Comment - Stamp added on another page (say page 3). I see similar message as above with 'Annotation Modified' - Stamp annot on page 3 on the signature panel. 

The signature was newly added, no other change. Is this normal, is there a way around it?

Thanks
miha