touch off on rotary axis leads to extremely weird results

I've searched the forums but haven't found anything even vaguely like this, so:
I just added a rotary axis to my mill. I have it set up to not home, while the other three axes home. I was running it and had moved the rotary axis around a bunch using MDI, so it had some reading, let's say 720 degrees, and I wrote a bit of gcode that assumed it would be at 0 degrees. Instead of adding a g0 a0, I thought hey I'll just touch off the a axis to 0. The number that showed up in the AXIS DRO was more like 690257308.0, and if I continued to hit touch off (with any value) the numbers got much larger until they began to overflow at about 30 digits or so. Since that axis is restricted to -9999 to 9999 degrees (the default, which may be arbitrary) as soon as things went wonky I couldn't do anything with that axis, in MDI or via gcode, because it was so far past the maximum.
I'm using an older version of linuxcnc, 2.4.3 (because my PC that had a newer version crashed catastrophically and won't even power up anymore) so this may no longer be a problem, but: has anyone seen this, ever? Or even anything like it? The A axis does show up as homed, since I set up the .ini for a no-homing-switch axis. I could add an index pulse on it and have it home to that. But I think there are times I'm going to want to touch off to a specific position, and would like to know if other people have done this and had it work okay.

I'm glad to hear that. I'll upgrade to a newer version and continue playing with it. Thanks!