xmbmon displays but no stats

From: Gary Aitken <freebsd_at_dreamchaser.org>
Date: Sun, 07 Apr 2024 18:45:24 UTC
Some time ago I had xmbmon working on this box;
have since upgraded OS several times, now at 13.2-RELEASE-p11

Originally installed using:
   pkg install xmbmon
but pkg info showed it was not built with X11
So did pkg delete and built with X11 option enabled

It now displays, but shows no stats (no lines on the graph)
If I run mbmon, I get stats:

$ mbmon 1

Temp.= 30.0, 128.0, 30.0; Rot.=  103, 7848,    0
Vcore = 3.76, 3.79; Volt. = 1.78, 3.74,  8.33,  -3.73, -3.13

$ mbmon -debug
Using ISA-IO access method!!
* Int.Tec.Exp. Chip IT8705F/IT8712F or SIS950 found.

I've tried
   xmbmon
   xmbmon -I 1
   xmbmon -A 1
   xmbmon -A -probe it87 1

what am I missing?
Thanks,

Gary