If you cut a dvar charif like an onion with a meaty knife and then eat the onion, are you then meaty and have to wait before eating milky?
You do not have to wait. The reason is because the absorbed taste that was eaten is not strong, as it is only nat bar nat.
R’ A. Eiger Y:D 89 on Shach 19, Igros Moshe Y:D 2-26, Kovetz M’bais Levi (Binyonei Y:D) pg. 34, Poskim. This applies even though we usually consider the taste of an onion to be a first degree taste, for this we are lenient.