Well, in my version of Maple, 15, firing up the application anew to make sure everything else is flushed out, I get a linear plot. I do not know how to post a plot here so I cannot produce the proof; it is the same curves as in Markiyan's post above; but with a linear vertical scale.
FWIW, here is my .mapleinit file. I do not see how this would prevent logplot in display.
print("Maple Init loaded...");
Somehow logplotting is really screwed up in 15; I already had the issue that logplot will ignore, for 15 digits, everything below 10^-7. This one even Maplesoft support verified and acknowledged as a bug (fixed in 16 and not present in 14).