plotdf doesn't seem to know about %pi or %e

[themusicgod1]

1) plotdf some function (doesn't seem to matter which
2) enter configuration for plotdf using the wrench icon
3) put something in that's a function of %e^x for dy/dt or dx/dt fields in dy/dt , dx/dt
eg %e^x for dx/dt and x for dy/dt
4) hit "OK"
result should be the same as if you put in
plotdf([%e^x,x],[x,-10,10],[y,-10,10]);
which does work

instead what happens is
error; syntax error

error : can't read a[0] no such element in array

xmaxima 5.38.1-8
ubuntu 17.04 zesty

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: maxima 5.38.1-8
ProcVersionSignature: Ubuntu 4.10.0-21.23-generic 4.10.11
Uname: Linux 4.10.0-21-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
CurrentDesktop: Unity:Unity7
Date: Fri May 26 23:43:37 2017
InstallationDate: Installed on 2017-04-18 (38 days ago)
InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
JournalErrors:
 Error: command ['journalctl', '-b', '--priority=warning', '--lines=1000'] failed with exit code 1: Hint: You are currently not seeing messages from other users and the system.
       Users in the 'systemd-journal' group can see all messages. Pass -q to
       turn off this notice.
 No journal files were opened due to insufficient permissions.
SourcePackage: maxima
UpgradeStatus: No upgrade log present (probably fresh install)