I have always told people that water will wick up into the ends of trim and door jambs if it is in contact with the threshold or concrete.
Therefore, sealing the tangent point between them would help prevent that.

Then, the other day for the first time, I see a manufactures sticker on a jamb indicating "Do not caulk here" with an arrow pointing to the same area.

Whats up?

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Absolute Home Inspections, LLC