Patterns that reliably precede a problem, documented

Patterns that reliably precede a problem, documented — setting out what I have, and where I think it stops being reliable.

A logistics question, since the answers here are usually better than anywhere else I have looked.

Parcel despatched 12 days ago, tracking last updated 4 days ago at a customs facility, no further movement. Cold pack included at despatch.

Two questions. First, at what point is this genuinely a problem rather than an ordinary delay? Second, if it does arrive, what is the actual decision process for assessing it, as opposed to the two extremes people usually offer?

Picking up the opening post: that is the part I would want checked first.

Anonymity: a supplier that will not disclose legal name, address, or responsible person is not operating in a way that allows accountability.

Documentation quality as a signal: a supplier that reports method identifiers, distinguishes specification from result, and states the counter-ion form is telling you something about systems behind the document. A certificate that is a number and a signature tells you less.

Evasion when asked: if a supplier does not clarify when asked specifically for method details, counter-ion form, or batch origin, that itself is a red flag worth documenting.

post #7 is right about the mechanism and I think understates the practical bit.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.