The common failure isn’t a forged or broken signature. It’s an advanced (non-qualified) signature that an organization has been treating, in practice, as if it carried the automatic legal presumption only a qualified signature has. Nobody notices until a specific signer denies signing, and the assumption gets tested for the first time in an actual dispute.
A counterparty disputes a signed agreement, claims they never signed it, or that the version they signed was different from the one being enforced. Someone pulls up the signed file expecting the signature to settle the question. What actually happens next depends entirely on what level that signature was, and whether anyone checked that before now.
A qualified electronic signature carries automatic legal equivalence to a handwritten signature under eIDAS Article 25, across the entire EU. The burden shifts to whoever is disputing it. This is the scenario the compliance function assumed was in place. See what is a qualified electronic signature?
An advanced electronic signature carries no automatic presumption. Article 25(1) means it can’t be denied legal effect solely for being electronic, but its validity in a specific dispute gets argued on the facts: was it genuinely linked to the signer, was it under their sole control, has the document been altered since. None of that is settled automatically the way it would be for a qualified signature. If the organization’s internal assumption was "our e-signatures are legally binding, full stop", this is the moment that assumption gets tested, in the middle of an active dispute rather than during a calm compliance review. See eIDAS Advanced vs Qualified: which level do you need?
Some signing platforms don’t embed a cryptographic seal in the file at all; whatever proof exists lives only in the platform’s own records. In a dispute, that means asking the platform, an interested party in some disputes, to vouch for its own signature, rather than checking the file independently. See the risk of platform-tied signatures.
Most signed documents are never disputed, which is exactly why the gap between assumed and actual compliance level can persist for years without being noticed. The cost of finding out the hard way isn’t just the individual dispute, it’s discovering, mid-dispute, that every other document signed the same way carries the same exposure.
Confirm what level your organization’s signing process actually produces, not what the vendor’s marketing implies, and confirm it per use case, since some organizations mix levels without realizing it. See a practical checklist for auditable digital signatures for the specific things to verify.