The stand going too far over centre is not an uncommon problem and results in the bike being much harder to get off the stand than to put it on.
Assuming the pivot bolts and bushes are not unduly worn the solution is to build up the ends of the stand with weld and grind back to shape. Look at where they butt up against the frame stops and you should see the wear. Part of the problem is that the stand ends are a laminated construction - basically the stand tubes are squashed flat with a filler piece in the middle. Building up with weld makes them solid and they can be thickened up a bit too for extra strength. I did mine last year and it has made a huge difference. Sorry I didn't take any in progress pics as I was too keen to get the thing finished and re-painted. You can see in the finished job how the ends have been thickened up. If you search this and other forums you will find many others have done something similar.
Don't do what I did and put the job off for a year or two as it will only get worse as more and more stress is put on the stand ends. And while we are on the topic of don't do what I did. Unless you want to spend a few happy hours with the angle grinder don't add too much weld. Enough so that it will grind back to about 1/8" thick at the tip makes a big difference.
