Installation variable name changed or deleted

Dear,
we have experienced the weird phenomena like the following

UR5
SW Version : 3.6.0.30507
Our installation variable is Foup1_ready_0.
After loading new program, Foup1_ready_0 is renamed as Foup1_ready_1 occasionally.
So loaded program is stayed incomlete programing state because Foup1_ready_0 does not exist.

Eventually variable name is changed to Foup_ready_2 and removed.

Is there anyone to see that case?