Ask-a-Dave's-Gardener: Strange Marks on Bamboo, 2 by TXBamboo

TXBamboo wrote:
I planted bamboo about 3 weeks ago, but within the last week these strange marks/scratches started appearing on multiple stalks. It doesnt appear to be aphids, fungus, or rot, and I cant find anything else that looks similar after searching online.

Did I over fertilize? We planted with an amended top soil, cow manure, covered with pine bark mulch, and fertilized as recommended by the nursery (which also hasnt been able to identify the issue).

Any thoughts or recommendations would be much appreciated!