they're a common occurrance in anime, mostly due to Japan not knowing the extensive history of why certain types of depictions of non-japanese people are not okay, that said they still aren't 100% excusable just for that reason, as many mangaka voluntarily revise the designs to make them less offensive when they realize the people complaining actually have a point
the best example being "008" from Cyborg 009,
in the original Manga, he was...well....HORRIFYINGLY RACIST LOOKING
mind you he is supposed to be a Human african man, but he looked like an actual ape, which is not okay, it's even worse than Mr. Popo
however the Author himself eventually realized that the design was not okay, and chose to give him this design for the 2001 series
future series redesigned him even further
making him look like this
then of couse comes the subject of Jynx and Popo themselves
they also do not look okay......though to date, only Jynx Design was altered
though just by making her purple like some of her poke-clones, namely the Gothic lolita pokemon line
while Popo...I guess Toei just has a "well it's too late to fix it now" mentality with Popo....since he's always looked like that
and also maybe becasue Electric Blue Popo was considered in it's own way to be even more offensive