CLOB is as you might know "character large object", a data type in Oracle (and others?).
Since SAS has limited to 32K for char variables, the information in your CLOBs might be truncated when accessing these using the SAS/ACCESS libname engine for your RDBMS.
A work around is to use explicit SQL pass-thru to access the data. If you need it in SAS, try to split the CLOB into smaller chunks, before accessing/importing it to SAS.
41575 - SAS/ACCESS® Interface to Oracle supports BLOB and CLOB data types with a character limit of ...
Data never sleeps