COPA characteristics updated with wild characters (####)

Hello Friends,

We have custom characteristics (WWXXX) for capturing contract number from sales order, which is stored in ZFIELD of VBAP table with enhancement.

This characteristics dervied properly upto last week. It means whereever contract number in VBAP table it is derived in characteristics WWXXX.

for the past two days the characteristics are updated with wild characters (####) in COPA document (we checked in KE23N-display copa document).

when we check the VBAP table we have contract number on that.

further when we check KE4ST - simulation it shows the contract number in value before column and after column.

Can anyone come across this type of issue? please share your expertise.

Thanks

VSN