Here we have an example of Oliver Cowdery’s occasional difficulty in reading the original manuscript. Scribe 3 of 𝓞 spelled heeded as heded, which Oliver initially misread as beheld. After initially writing “but we beheld them not” in 𝓟, Oliver immediately caught his error, crossed out beheld, and supralinearly wrote headed. But then Oliver suddenly recalled the correct spelling, crossed out the supralinear correction, and wrote heeded inline. In this instance, Oliver Cowdery caught his misspelling; for an example where his misspelling of heed as head led to a textual misinterpretation and subsequent change in the text, see Alma 51:15.
Summary: Maintain the reading of the original manuscript in 1 Nephi 8:33 (“but we heeded them not”), obviously the correct interpretation of scribe 3’s “but we heded them not”.