Comment by antonvs

The Late Heavy Bombardment has increasingly been called into question.

Here’s one article about it: https://phys.org/news/2016-10-apollo-era-evidence-late-heavy...

The “definitive evidence remains elusive” from your quote is probably a hint: the LHB was a result of getting carried away extrapolating from the Apollo samples due to an early dearth of data, not a real phenomenon.