Whatīs this

Can tune it as often i want, after a few minutes, about 5-10, itīs a little bit higher or deeper, 5-10 cents.
Sometimes all voices the same, sometimes differences in the voices. (Round robin, so i can see )
Deleted the tuning tables several times.
OS 201 is on it, i donīt want the new 2.04 because of the change from the velocity-holf-function (loudness).
If itīs a few cents out of tune after a few minutes i can switch power off and on and then itīs in tune, but also
only for a few minutes ?!?
Iīm afraid, thereīs a real defect that the synth "forgets" the tuningtable...
Anyone an idea ?