Nepenthes don't make bulbs or rhizomes; the Indochinese species and a couple others may make thick taproots to survive dry seasons but that is very different from this. I would be worried about some sort of fungal or bacterial infection causing outgrowths if it's actually a part of the plant and not a compacted soil component.
There is some interesting information out there about N. rhombicaulis, angasanensis, or minima concerning Nepenthes that seem to produce rhizomes. I'm no authority on the subject, but it could be worth looking into.
Due to the appearance and very odd placement of those root "rhyzomes" to me, they appear to be bacterial or insect related. I've had issues with root knot nematodes which deal similar damage to my Sarracenia rescues, specifically ones that were placed near farms
From what I've seen thus far minima doesn't exist; the traits that supposedly separate it from maxima, other than smaller size, have all been unreliable on plants that have been cultivated as well as a few photos from the wild that show it, and I also haven't seen any actual photos surface yet of the supposed taproot it has that's any different from what maxima can produce.
But that aside: it's still a thickened root system they develop, it's not a rhizome which is a stem converted to a storage organ (think Sarracenia or irises), and never forms in random bulbs but rather a taproot style.