White nubs on plant?

Hello everyone, first post on here
I’ve got my lil garden going in the closet (400w HPS, 18hr on 6 off, growing in fox farm happy frog in 1 gallon root pouches to start) and I’ve noticed on two on my white rhinos that there are these strange looking white nubs on the main stem between the 1st and 2nd node and at every site where node meets main stem. Is this an issue? Should I kill or am I just being paranoid? Any input appreciated, cheers
 
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