This story is something that happened to me, when received my U1272A four years back.
The problem was that Tilt Bail Stand did not lock in place properly and was coming back out.
In order to correct this I came to the conclusion that Tilt Bail needs some correction and I did my experiments with extreme caution because I was not aware of the meting point of the plastic Tilt Bail Stand.
By selecting the proper in dimensions metal nut and by using hot air (with extreme caution) I did manage to reform the axle that has the lock ball, so to expand few more millimeter so to lock in place for good.
After all this years I never feel the need to repeat this process, therefore my fix seems even today as a permanent one.
But I am suggesting this to any one who needs it, in case that the frequently use of the Tilt Bail Stand on your multimeter become the reason of causing trouble to this lock point.