Hello Karthik,
I'm pretty sure that you are run into known ASE bug CR 780810 which is fixed in >= 16.0.01.01 .
Please read also related KBA
"2144033 - SAP ASE: REORG DEFRAG WITH SKIP_COMPACT_EXTENTS might fail with ASE error 605"
and ASE 16.0.01.01 Targeted CR List
"2150561 - Targeted CR List for ASE 16.0 SP01 PL01".
My recommendation is to upgrade to ASE version 16.0.01.02 to avoid this error in future.
Best regards
Christoph