I happened to read an article yesterday which reported that this discovery had been shown to be likely the result of volcanic activity and nothing to do with bacteria. I went to dig out the source of this claim, in
D. Wacey, M. Saunders, and C. Kong, ‘Remarkably preserved tephra from the 3430 Ma Strelley Pool Formation, Western Australia: Implications for the interpretation of Precambrian microfossils’, Earth and Planetary Science Letters, vol. 487, pp. 33—43, Apr. 2018..
In defence of the idea that the Canadian discovery was volcanogenic in origin, they invited me to compare their fig 2c, with fig 2e from the original paper. I have done so below.
I can't honestly say this exercise has left me feeling particularly enlightened.