I've hust found a strange behaviour with this instruction:
with an existing value of 1, instead of generating a single -1 row to obtain a total of 0, it generates 59 identical row of -1 and the total is -58
59 is not significant for me, not the total number of the entities nor the number of entities involved in the use of the account CTL_FLAG....
Moreover the logic has not been modified for 2/3 years and it was working fine. I had no opportunity to check system/software configuration for changes...
Any idea on what to check???