As of 12.6.3 This is a hardcoded limit, configurable only by changing an OOTB file that will be overwritten next time you upgrade.
By default, out of the box, the worklist can only show 100 items.
Edit the file iam_im.ear\workflow.rar\META-INF\ra.xml as follows to
raise the limit:
raising this limit too high can cause performance issues. Let me
know if this resolves the issue. This will be overwritten on upgrade.