Why is one of these two itext 7 signed and validated document is not valid with Adobe DC reader?

Question

I\'ve two pdf documents certified (signed and validated with the same mechanism based on Itext 7 ) and when i use adobe reader DC to check their validity, only one has the

Answer 1

Since multiple other tools validate these two documents without any issue ...we may think that's an adobe reader bug.

In particular as Adobe Acrobat is itself is torn: