Starting with the example code given for nested progress bars, I've tried the following:

from tqdm import trange, tqdm
from time import sleep

for i in trange(10, desc='1st loop'):
    tqdm.write("%s" % i)
    for j in trange(5, desc='2nd loop', leave=False):
	tqdm.write("%s, %s" % (i, j))
        for k in trange(100, desc='3nd loop'):
            tqdm.write("%s, %s, %s" % (i,j,k))
            sleep(0.01)

Under python 2.7 this works as expected, the log messages are written above the three nested progress bars at the bottom of the console.

On python 3.6, the log messages appear to overwrite the progress bars, which are rapidly scrolled off-screen (by new log messages) as soon as they are updated.

Maybe this is related to #348 -- applying the patch suggested in #331 does not fix the problem, however.

This is on MacOS Sierra, using the stock Terminal app.