I have recently updated to r-tmap 3.3_1 via conda-forge channel to overcome a previous known issue #524, and I just noticed that another minor issue emerged in this latest version: displaying the histogram on the legend of bubble charts causes the print of the color palette hex codes.

library(tmap)
data("World")

tm_shape(World) +
    tm_borders() +
    tm_bubbles(col = "pop_est",
               size = "area",
               legend.hist = TRUE)

I guess this is an easy fix, maybe just a print() command left uncommented somewhere.
It would be great getting that nice feature back to work without undesired prints.